Device and method for transmitting data in wireless power transmission system

ABSTRACT

The present invention relates to a device and method for transmitting data in a wireless power transmission system. The present specification discloses a wireless power reception device comprising: a power pickup unit configured to receive wireless power from a wireless power transmission device by magnetic coupling with the wireless power transmission device, and convert an AC signal generated by the wireless power into a DC signal; a communication/control unit configured to receive the DC signal from the power pickup unit and perform control of the wireless power; and a load configured to receive the DC signal from the power pickup unit. According to the present invention, a large amount of data can be easily exchanged between a wireless power transmission device and a wireless power reception device by adjusting a transmission time interval of a control error packet (CEP) and a timeout of the CEP.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

The present disclosure relates to wireless power transmission and, moreparticularly, to an apparatus and a method for transmitting data in awireless power transmission system.

Related Art

Wireless power transmission technology is a technology that transmitselectrical power without wires between a power source and an electronicdevice. As one example, the wireless power transmission technologyallows the battery of a wireless terminal such as a smartphone or tabletto be charged simply by placing the wireless terminal on a wirelesscharging pad, thereby providing better mobility, convenience, and safetythan the existing wired charging environment using a wired chargingconnector. The wireless power transmission technology is getting greatattention as a means to replace the existing wired power transmissionenvironment not only for wireless charging of wireless terminals butalso for various other applications including electric vehicle, wearabledevice such as Bluetooth earphones or 3D glasses, home appliance,furniture, underground facility, building, medical device, robot, andleisure.

Wireless power transmission is also called contactless powertransmission, no point of contact power transmission, or wirelesscharging. A wireless power transmission system may comprise a wirelesspower transmitter providing electrical energy through a wireless powertransmission method and a wireless power receiver receiving electricalenergy transmitted wirelessly from the wireless power transmitter andsupplying power to a power receiving device such as a battery cell.

The wireless power transmission technology encompasses various methodssuch as a method for transmitting power through magnetic coupling,method for transmitting power through radio frequency (RF), method fortransmitting power through microwaves, and method for transmitting powerthrough ultrasonic waves. Magnetic coupling based methods are furtherdivided into magnetic induction and magnetic resonance methods. Themagnetic induction method transmits energy by using currents induced ina receiver-side coil due to the magnetic field generated at atransmitter-side coil battery cell according to electromagnetic couplingbetween the transmitter-side coil and the receiver-side coil. Themagnetic resonance method is similar to the magnetic induction method inthat it uses a magnetic field. However, the magnetic resonance method isdifferent from the magnetic induction method in that resonance isgenerated when a specific resonant frequency is applied to thetransmitter-side and receiver-side coils; and energy is transferred as amagnetic field is concentrated due to the generated resonance at bothends of the transmitter and receiver-sides.

In general, the magnetic induction method operates according to thestandard specification of the Wireless Power Consortium (WPC). Accordingto the WPC standard specification, a wireless power transmitter and awireless power receiver may communicate with each other. In this case,data communication from the wireless power transmitter to the wirelesspower receiver employs the Frequency Shift Keying (FSK) scheme whiledata communication from the wireless power receiver to the wirelesspower transmitter employs the Amplitude Shift Keying (ASK) scheme.

Data may be transmitted in a control error interval. However, since thetime period during which data may be transmitted is limited by thecontrol error interval, the amount of data which may be transferredwithin a predetermined time period is limited. In addition, althoughcommunication from a wireless power transmitter to a wireless powerreceiver is performed according to the FSK scheme, the FSK scheme has alimitation in transmitting a large amount of data since the FSK schemeexhibits a slow transfer rate by its inherent nature. Moreover, sincethe length of data packets transmitted at the control error intervals isfixed, if the control error interval becomes shorter than the length ofa data packet according to variation of payload due to vibration orimpact, it is not possible to send data at the corresponding intervals.Therefore, although wireless charging may involve a process forexchanging a large amount of data between a wireless power transmitterand a wireless power receiver to utilize an additional function such asan authentication procedure in a future, the prior art requires aconsiderable time to perform the process.

SUMMARY OF THE DISCLOSURE

The technical object of the present disclosure is to provide anapparatus and method for transmitting data in a wireless powertransmission system.

Another technical object of the present disclosure is to provide a timeinterval between control error packets applied to a wireless powertransmitter and a wireless power receiver developed based on thestandard specification v1.3 of the Wireless Power Consortium (WPC).

Yet another technical object of the present disclosure is to provide amethod for exchanging data when two-way communication is performed basedon extended power profile (EPP) of the WPC standard; and a time intervalbetween control error packets applied to the wireless power transmitterand wireless power receiver.

Still another technical object of the present disclosure is to provide awireless power transmitter and a method for the transmitter; and awireless power receiver and a method for the receiver which improveperformance of a data transmission protocol in a new standard of theWPC.

According to one aspect of the present disclosure, a wireless powerreceiver receiving wireless power from a wireless power transmitter andtransmitting a control packet to the wireless power transmitter in awireless power transfer system is provided. The apparatus comprises apower pick-up unit configured to receive wireless power from thewireless power transmitter via magnetic coupling with the wireless powertransmitter and to convert an AC signal generated by the wireless powerto a DC signal; a communication/control unit configured to receive theDC signal from the power pick-up unit and to perform control of thewireless power; and a load configured to receive the DC signal from thepower pick-up unit.

Here, based on a type of a power profile and a version of wireless powertransfer standard with which the wireless power reception and thewireless power transmitter comply, the communication/control unit may beconfigured to transmit a control error packet including a control errorvalue for the wireless power to the wireless power transmitter in afirst time interval or a second time interval larger than the first timeinterval.

In one aspect, if the version of the wireless power transfer standard isthe first version, the communication/control unit may transmit thecontrol error packet in the first time interval while, if the version ofthe wireless power transfer standard is the second version higher thanthe first version and the type of the power profile is extended powerprofile (EPP), the communication/control unit may transmit the controlerror packet in the second time interval.

In another aspect, if the version of the wireless power transferstandard is the first version, the communication/control unit maytransmit the control error packet in the first time interval while, ifthe version of the wireless power transfer standard is the secondversion higher than the first version, the type of the power profile isEPP, and transmission of a data packet is needed, thecommunication/control unit may transmit the control error packet in thesecond time interval.

In yet another aspect, the wireless power transfer standard may be theWireless Power Consortium (WPC) specification, the first version may belower than v1.3, and the second version may be v1.3.

In still another aspect, the first time interval may be larger than thesecond time interval by two times or more.

In still yet another aspect, according to the type of power profile andthe version of wireless power transfer standard with which the wirelesspower receiver and the wireless power transmitter comply, time-out ofthe control error packet may be determined as a first time-out or asecond time-out larger than the first time-out.

In a still further aspect, if the version of the wireless power transferstandard is the first version, the time-out for the control error packetmay be determined as the first time-out while, if the version of thewireless power transfer standard is the second version higher than thefirst version and type of the power profile is EPP, the time-out for thecontrol error packet may be determined as the second time-out.

In a still yet further aspect, the first time interval may be smallerthan the first time-out, and the second time interval may be smallerthan the second time-out.

According to another aspect of the present disclosure, a wireless powertransmitter transmitting wireless power to a wireless power receiver andreceiving a control packet from the wireless power receiver in awireless power transfer system is provided. The apparatus comprises apower conversion unit configured to transmit wireless power to thewireless power receiver via magnetic coupling with the wireless powerreceiver; and a communication/control unit configured to receive acontrol error packet including a control error value for the wirelesspower from the wireless power receiver in a first time interval or asecond time interval larger than the first time interval based on thetype of power profile and the version of wireless power transferstandard with which the wireless power receiver and the wireless powertransmitter comply.

In one aspect, if the version of the wireless power transfer standard isthe first version, the communication/control unit may receive thecontrol error packet in the first time interval while, if the version ofthe wireless power transfer standard is the second version higher thanthe first version and the type of the power profile is extended powerprofile (EPP), the communication/control unit may receive the controlerror packet in the second time interval.

In another aspect, if the version of the wireless power transferstandard is the first version, the communication/control unit mayreceive the control error packet in the first time interval while, ifthe version of the wireless power transfer standard is the secondversion higher than the first version, the type of the power profile isEPP, and transmission of a data packet is needed, thecommunication/control unit may receive the control error packet in thesecond time interval.

In yet another aspect, the wireless power transfer standard may be theWireless Power Consortium (WPC) specification, the first version may belower than v1.3, and the second version may be v1.3.

In still another aspect, the first time interval may be larger than thesecond time interval by two times or more.

In still yet another aspect, according to the type of power profile andthe version of wireless power transfer standard with which the wirelesspower receiver and the wireless power transmitter comply, time-out ofthe control error packet may be determined as a first time-out or asecond time-out larger than the first time-out.

In a still further aspect, if the version of the wireless power transferstandard is the first version, the time-out for the control error packetmay be determined as the first time-out while, if the version of thewireless power transfer standard is the second version higher than thefirst version and the type of the power profile is EPP, the time-out forthe control error packet may be determined as the second time-out.

In a still yet further aspect, the first time interval may be smallerthan the first time-out, and the second time interval may be smallerthan the second time-out.

According to the present disclosure, by adjusting a time intervalbetween control error packets (CEPs) and time-out of the CEP, a largeamount of data may be exchanged easily between a wireless powertransmitter and a wireless power receiver; a period of time beforetransmission of wireless power is initiated may be reduced; and anadditional function such as an authentication procedure involvingexchange of a large amount of data may be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of a wireless power transmissionsystem 10 according to one embodiment.

FIG. 2 illustrates a block diagram of a wireless power transmissionsystem 10 according to another embodiment.

FIG. 3a illustrates examples of various electronic devices where awireless power transmission system is employed.

FIG. 3b illustrates one example of WPC NDEF in a wireless powertransmission system.

FIG. 4a illustrates a block diagram of a wireless power transmissionsystem according to another embodiment.

FIG. 4b illustrates one example of Bluetooth communication architectureto which the present disclosure may be applied.

FIG. 4c illustrates a block diagram of a wireless power transmissionsystem employing BLE communication according to one example.

FIG. 4d illustrates a block diagram of a wireless power transmissionsystem employing BLE communication according to another example.

FIG. 5 is a state transition diagram illustrating a wireless powertransfer procedure.

FIG. 6 illustrates a power control method according to one embodiment.

FIG. 7 illustrates a block diagram of a wireless power transmitteraccording to another embodiment.

FIG. 8 illustrates a block diagram of a wireless power receiveraccording to another embodiment.

FIG. 9 illustrates a communication frame structure according to oneembodiment.

FIG. 10 illustrates a structure of a sync pattern according to oneembodiment.

FIG. 11 illustrates operation states of a wireless power transmitter anda wireless power receiver in a shared mode according to one embodiment.

FIG. 12 illustrates a wireless charging certificate format according toone embodiment.

FIG. 13 illustrates a data stream at an application level between awireless power transmitter and a wireless power receiver according toone embodiment.

FIG. 14 illustrates a method for exchanging data between a wirelesspower transmitter and a wireless power receiver based on a first timeinterval according to one embodiment.

FIG. 15 is a flow diagram illustrating operations of a wireless powerreceiver in exchanging data between the wireless power receiver and awireless power transmitter according to the method described withreference to FIG. 14.

FIG. 16 illustrates a method for exchanging data between a wirelesspower transmitter and a wireless power receiver based on a second timeinterval according to another embodiment.

FIG. 17 is a flow diagram illustrating operations of a wireless powerreceiver in exchanging data between the wireless power receiver and awireless power transmitter according to the method described withreference to FIG. 16.

FIG. 18 is a flow diagram illustrating operations of a wireless powertransmitter in exchanging data between a wireless power receiver and thewireless power transmitter according to one embodiment.

FIG. 19 is a flow diagram illustrating operations of a wireless powerreceiver in exchanging data between a wireless power receiver and thewireless power transmitter according to another embodiment.

FIG. 20 is a flow diagram illustrating a method for exchanging databetween a wireless power transmitter and a wireless power receiveraccording to another embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The term “wireless power” used hereinafter refers to energy of arbitraryform related to electric, magnetic, and electromagnetic fieldstransferred from a wireless power transmitter to a wireless powerreceiver without using physical electromagnetic conductors. Wirelesspower may be called a wireless power signal and may refer to theoscillating magnetic flux enclosed by the primary and secondary coils.For example, this document describes power conversion in a system forcharging devices including a mobile phone, cordless phone, iPod, MP3player, and headset wirelessly. In general, the basic principles ofwireless power transfer include power transfer through magneticcoupling, power transfer through radio frequency (RF), power transferthrough microwaves, and power transfer through ultrasonic waves.

FIG. 1 illustrates a block diagram of a wireless power transmissionsystem 10 according to one embodiment, and FIG. 2 illustrates a blockdiagram of a wireless power transmission system 10 according to anotherembodiment.

Referring to FIG. 1, the wireless power transmission system 10 includesa wireless power transmitter 100 and a wireless power receiver 200.

The wireless power transmitter 100 receives power from an external powersource S and generates a magnetic field. The wireless power receiver 200receives power wirelessly by generating currents by using the generatedmagnetic field.

Also, the wireless power transmitter 100 and the wireless power receiver200 in the wireless power transmission system 10 may transmit andreceive various pieces of information required for wireless powertransfer. Here, communication between the wireless power transmitter 100and the wireless power receiver 200 may be performed according to eitherin-band communication using a magnetic field used for wireless powertransfer or out-band communication using a separate communicationcarrier. Out-band communication may also be called out-of-bandcommunication. In what follows, the terms are unified as out-bandcommunication. Examples of out-band communication include NFC,Bluetooth, and Bluetooth Low Energy (BLE).

Here, the wireless power transmitter 100 may be provided as a fixed ormobile type. Examples of fixed type transmitter include transmittersembedded in the indoor ceiling or wall or furniture such as a table;installed in the form of an implant in an outdoor parking lot, bus stopor subway station; or installed in a transportation means such as avehicle or a train. The mobile type wireless power transmitter 100 maybe implemented as a mobile device with a portable weight or size or aspart of another device such as a cover of a notebook computer.

The wireless power receiver 200 should be construed as a comprehensiveconcept including various types of electronic devices equipped with abattery and various home appliances driven by receiving power wirelesslyrather than through a power cable. Typical examples of the wirelesspower receiver 200 include a portable terminal, cellular phone, smartphone, Personal Digital Assistant (PDA), Portable Media Player (PMP),Wibro terminal, tablet, phablet, notebook, digital camera, navigationterminal, television, and electric vehicle (EV).

In the wireless power transmission system 10, the number of wirelesspower receiver 200 may be one or plural. Although FIG. 1 illustrates acase where the wireless power transmitter 100 and the wireless powerreceiver 200 transmit and receive power one-to-one, it is also possiblethat one wireless power transmitter 100 transmits power to a pluralityof wireless power receivers 200-1, 200-2, . . . , 200-M. In particular,when wireless power transmission is conducted through a magneticresonance scheme, one wireless power transmitter 100 may transmit powerto multiple wireless power receivers 200-1, 200-2, . . . , 200-Msimultaneously by applying a simultaneous transmission scheme or atime-division transmission scheme.

Also, although FIG. 1 illustrates a case where the wireless powertransmitter 100 transmits power directly to the wireless power receiver200, a separate transceiver such as a relay or repeater for increasingthe wireless power transmission range may be introduced between thewireless power transmitter 100 and the wireless power receiver 200. Inthis case, power is transmitted from the wireless power transmitter 100to the wireless power transceiver, and the wireless power transceiveragain transmits power to the wireless power receiver 200.

In what follows, a wireless power receiver, power receiver, and receivermentioned in the present specification refer to the wireless powerreceiver 200. Also, a wireless power transmitter, power transmitter, andtransmitter mentioned in the present specification refer to the wirelesspower transmitter 100.

FIG. 3a illustrates examples of various electronic devices where awireless power transmission system is employed, and FIG. 3b illustratesone example of WPC NDEF in a wireless power transmission system.

FIG. 3a illustrates electronic devices categorized according to theamount of power transmitted and received in a wireless powertransmission system. Referring to FIG. 3a , a small power (smaller thanabout 5 W or 20 W) wireless charging scheme may be applied to wearabledevices such as a smart watch, smart glasses, Head Mounted Display(HMD), and smart ring; and mobile electronic devices (or portableelectronic devices) such as an earphone, remote controller, smart phone,PDA, and tablet PC.

A medium power (smaller than about 50 W or 200 W) wireless chargingscheme may be applied to medium-size/small-sized home appliances such asa notebook computer, robot vacuum cleaner, TV, audio device, vacuumcleaner, and monitor. A high power (small than about 2 kW or 22 kW)wireless charging scheme may be applied to kitchen appliances such as ablender, microwave oven, and electric rice cooker; and personal mobilitydevices (or electric device/mobility means) such as a wheelchair,electric kickboard, electric bicycle, and electric vehicle.

The electronic devices/mobility means described above (or shown inFIG. 1) may each include a wireless power receiver to be describedlater. Therefore, the aforementioned electronic devices/mobility meansmay be charged by receiving power wirelessly from a wireless powertransmitter.

In what follows, descriptions are given with respect to a mobile deviceto which a wireless power charging scheme is applied, which is, however,only an example; a wireless charging method according to the presentdisclosure may be applied to various electronic devices described above.

Standards related to wireless power transmission include those developedby the Wireless Power Consortium (WPC), Air Fuel Alliance (AFA), andPower Matters Alliance (PMA).

WPC standards define baseline power profile (BPP) and extended powerprofile (EPP). BPP is related to a wireless power transmitter and awireless power receiver which support 5 W power transmission, and EPP isrelated to a wireless power transmitter and a wireless power receiverwhich support transmission of power in the range larger than 5 W andless than 30 W.

Various wireless power transmitters and receivers using different powerlevels are dealt with by the respective standards and classified intodifferent power classes or categories.

For example, the WPC classifies wireless power transmitters andreceivers in terms of power class (PC)-1, PC0, PC1, and PC2; andprovides standard specifications for the respective PCs. The PC-1standard is related to wireless power transmitters and receivers thatprovide guaranteed power less than 5 W. Applications of the PC-1 includewearable devices such as smart watches.

The PC0 standard is related to wireless power transmitters and receiversproviding guaranteed power of 5 W. The PC0 standard includes the EPP inwhich guaranteed power reaches up to 30 W. Although in-band (IB)communication is a mandatory communication protocol for the PC0 class,out-band (OB) communication, which is used as a backup channel of theoption, may also be used. A wireless power receiver may determinewhether OB is supported by setting an OB flag within a configurationpacket. A wireless power transmitter supporting the OB may enter the OBhandover phase by transmitting a bit-pattern for OB handover as aresponse to the configuration packet. The response to the configurationpacket may be NAK, ND, or a newly defined 8-bit pattern. Applications ofthe PC0 include smart phones.

The PC1 standard is related to wireless power transmitter and receiversproviding guaranteed power ranging from 30 W to 150 W. OB is a mandatorycommunication channel for the PC1 class, and IB is used forinitialization and link establishment toward OB. A wireless powertransmitter may enter the OB handover phase by transmitting abit-pattern for OB handover as a response to the configuration packet.Applications of the PC1 include lap-top computers or power tools.

The PC2 standard is related to wireless power transmitter and receiversproviding guaranteed power ranging from 200 W to 2 kW, applications ofwhich include kitchen appliances.

As described above, PCs may be distinguished according to the powerlevel, and whether to support compatibility within the same PC may beset as optional or mandatory. Here, compatibility within the same PCindicates that power transmission and reception is possible within thesame PC. For example, if a wireless power transmission of PC x is ableto charge a wireless power receiver in the same PC x, it may be regardedthat compatibility is maintained within the same PC. Similarly to thecase above, compatibility between different PCs may also be supported.Here, compatibility between different PCs indicates that powertransmission and reception is possible between different PCs. Forexample, if a wireless power transmitter of PC x is able to charge awireless power receiver in PC y, it may be regarded that compatibilityis maintained between different PCs.

Support of compatibility between PCs is a very important issue from aperspective of user experience and infrastructure development. However,maintaining compatibility between PCs cause various technical problemsas follows.

In the case of compatibility within the same PC, for example, a wirelesspower receiver based on a lap-top charging scheme capable of providingreliable charging only when power is transmitted continuously may runinto a problem in receiving power reliably from a wireless powertransmitter based on a power tool scheme that transmits powerdiscontinuously. Also, in the case of compatibility between differentPCs, for example, when a wireless power transmitter of which the minimumguaranteed power is 200 W transmits power to a wireless power receiverof which the maximum guaranteed power is 5 W, there is a risk that thewireless power receiver is damaged due to overvoltage. As a result, itis difficult to take the PC as an indicator/reference thatrepresents/indicates compatibility.

Wireless power transmitters and receivers may provide very convenientuser experience and interface (UX/UI). In other words, a smart wirelesscharging service may be provided. A smart wireless charging service maybe implemented based on the UX/UI of the smart phone including awireless power transmitter. To implement the application, an interfacebetween the processor of the smart phone and the wireless power receiverallows “drop and play” two-way communication between the wireless powertransmitter and receiver.

As one example, a user may experience a smart wireless charging serviceat a hotel. If the user comes into a hotel room and places his or hersmart phone on a wireless charger in the room, the wireless chargertransmits wireless power to the smart phone, and the smart phonereceives wireless power. During this process, the wireless chargertransmits, to the smart phone, information about a smart wirelesscharging service. If the smart phone detects that it is placed on thewireless charger, detects reception of wireless power, or receivesinformation about the smart wireless charging service from the wirelesscharger, the smart phone enters a state in which it asks the user toopt-in into an additional feature. To this purpose, the smart phone maydisplay a message on the screen with or without an alarm sound. Oneexample of the message may include sentences such as “Welcome to ###hotel. Select “Yes” to activate smart charging functions: Yes|NoThanks”. The smart phone receives a user input selecting Yes or NoThanks and performs the next procedure selected by the user. If Yes isselected, the smart phone transmits the corresponding information to thewireless charger. And the smart phone and the wireless charger performthe smart charging function together.

The smart wireless charging service may also include receivingauto-filled WiFi credentials. For example, the wireless chargertransmits the WiFi credentials to the smart phone, and the smart phoneautomatically inputs the WiFi credentials received from the wirelesscharger by executing an appropriate app.

The smart wireless charging service may also include executing a hotelapplication that provides a hotel promotion or obtaining remotecheck-in/check-out and contact information.

As another example, the user may experience the smart wireless chargingservice inside a vehicle. If the user gets into the vehicle and places asmart phone on a wireless charger, the wireless charger transmitswireless power to the smart phone, and the smart phone receives wirelesspower. During this process, the wireless charger transmits informationabout the smart wireless charging service to the smart phone. If thesmart phone detects that it is placed on the wireless charger, detectsreception of wireless power, or receives information about the smartwireless charging service from the wireless charger, the smart phoneenters a state in which it inquires the user about the identity.

In this state, the smart phone is automatically connected to the vehiclevia WiFi and/or Bluetooth. the smart phone may display a message on thescreen with or without an alarm sound. One example of the message mayinclude sentences such as “Welcome to your car. Select “Yes” to synchdevice with in-car controls: Yes|No Thanks”. The smart phone receives auser input selecting Yes or No Thanks and performs the next procedureselected by the user. If Yes is selected, the smart phone transmits thecorresponding information to the wireless charger. And by executingin-vehicle application/display software, the smart phone and wirelesscharger may perform the in-vehicle smart control function together. Theuser may enjoy desired music and check a regular map position. Thein-vehicle application/display software may include a function thatprovides synchronized access for passersby.

As yet another example, the user may experience smart wireless chargingat home. If the user enters a room and places his or her smart phone ona wireless charger in the room, the wireless charger transmits wirelesspower to the smart phone, and the smart phone receives wireless power.During this process, the wireless charger transmits, to the smart phone,information about a smart wireless charging service. If the smart phonedetects that it is placed on the wireless charger, detects reception ofwireless power, or receives information about the smart wirelesscharging service from the wireless charger, the smart phone enters astate in which it asks the user to opt-in into an additional feature. Tothis purpose, the smart phone may display a message on the screen withor without an alarm sound. One example of the message may includesentences such as “Hi xxx, Would you like to activate night mode andsecure the building?: Yes No Thanks”. The smart phone receives a userinput selecting Yes or No Thanks and performs the next procedureselected by the user. If Yes is selected, the smart phone transmits thecorresponding information to the wireless charger. The smart phone andthe wireless charger may at least recognize the user pattern andrecommend the user to lock doors and windows, turn off lights, or set analarm.

In what follows, ‘profile’ will be newly defined as anindicator/reference that represents/indicates compatibility. In otherwords, it may be construed that compatibility is maintained amongwireless power transmitters and receivers having the same ‘profile’ toenable stable power transmission and reception whereas powertransmission and reception is impossible among wireless powertransmitters and receivers having different ‘profiles’. The profile maybe defined according to compatibility and/or application regardless of(or independently of) power class.

For example, profiles may be divided largely into four cases: i) mobile,ii) power tool, iii) kitchen, and iv) wearable profile.

In the case of ‘mobile’ profile, PC may be defined as PC0 and/or PC1;communication protocol/scheme as IB and OB; and operating frequencyranges from 87 kHz to 205 kHz, where examples of application includesmart phones and lap-top computers.

In the case of ‘power tool’ profile, PC may be defined as PC1;communication protocol/scheme as IB; and operating frequency ranges from87 kHz to 145 kHz, where examples of application include power tools.

In the case of ‘kitchen’ profile, PC may be defined as PC2;communication protocol/scheme as NFC-based; and operating frequency isless than 100 kHz, where examples of application include kitchen or homeappliances.

In the case of power tool and kitchen profiles, NFC communication may beemployed between a wireless power transmitter and receiver. Byexchanging WPC NFC Data Exchange Profile Format (NDEF), the wirelesspower transmitter and receiver may confirm that they are NFC devices.For example, as shown in FIG. 3b , the WPC NDEF may include applicationprofile field (for example, IB), version field (for example, IB), andprofile specific data (for example, IB). The application profile fieldindicates whether the corresponding apparatus uses i) mobile andcomputing, ii) power tool, or iii) kitchen profile; upper nibble of theversion field indicates the major version; and lower nibble of theversion field indicates the minor version. Also, the profile specificdata defines contents for kitchen.

In the case of ‘wearable’ profile, PC may be defined as PC-1;communication protocol/scheme as IB; and operating frequency ranges from87 kHz to 205 kHz, where examples of application include wearabledevices worn on the user's body.

Maintaining compatibility may be mandatory in the same profile, butoptional between different profiles.

The profiles described above (mobile profile, power tool profile,kitchen profile, and wearable profile) may be generalized to first ton-th profiles, and new profiles may be added to/substituted for oldprofiles according to the WPC specification and embodiments.

In case profiles are defined as described above, a wireless powertransmitter may perform power transmission selectively only to thewireless power receiver of the same profile as the wireless powertransmitter, thereby enabling more stable power transmission. Also,since the burden on the wireless power transmitter is reduced, and powertransmission to incompatible wireless power receivers is not attempted,the risk of damaging a wireless power receiver is reduced.

The PC1 in the ‘mobile’ profile may be defined by borrowing an optionalextension such as OB based on the PC0 while, in the case of ‘power tool’profile, it may be defined simply as a modified version of the PC1‘mobile’ profile. Also, until now, the wireless transmission technologyhas been defined in an attempt to maintain compatibility within the sameprofile; however, in the future, it may be further developed in adirection of maintaining compatibility between different profiles.

The AFA standard refers to a wireless power transmitter as a PowerTransmitting Unit (PTU) and refers to a wireless power receiver as aPower Receiving Unit (PRU). PTUs are classified into a plurality ofclasses as shown in Table 1, and PRUs are classified into a plurality ofcategories as shown in Table 2.

TABLE 1 Minimum Category Minimum Value for Support Maximum DevicesP_(TX) _(—) _(IN) _(—) _(MAX) Requirements Supported Class 1 2 W 1xCategory 1 1x Category 1 Class 2 10 W 1x Category 3 2x Category 2 Class3 16 W 1x Category 4 2x Category 3 Class 4 33 W 1x Category 5 3xCategory 3 Class 5 50 W 1x Category 6 4x Category 3 Class 6 70 W 1xCategory 7 5x Category 3

TABLE 2 PRU P_(RX) _(—) _(OUT) _(—) _(MAX) Example Applications Category1 TBD Bluetooth headset Category 2 3.5 W Feature phone Category 3 6.5 WSmart phone Category 4 13 W Tablet, Phablet Category 5 25 W Laptop witha small form factor Category 6 37.5 W Regular laptop Category 7 50 WHome appliance

As shown in Table 1, the maximum output power capability of a class nPUT is larger than or equal to the P_(Tx_IN_MAX) value of thecorresponding class. A PRU is not allowed to draw larger power thanspecified in the corresponding category. FIG. 4a illustrates a blockdiagram of a wireless power transmission system according to anotherembodiment. FIG. 4b illustrates one example of Bluetooth communicationarchitecture to which the present disclosure may be applied.

Referring to FIG. 4a , the wireless power transmission system 10includes a mobile device 450 receiving power wirelessly and a basestation 400 transmitting power wirelessly.

The base station 400 provides inductive power or resonant power and mayinclude at least one wireless power transmitter 100 and a system unit405. The wireless power transmitter 100 may transmit inductive orresonant power and control transmission. The wireless power transmitter100 may include a power conversion unit 110 that converts electricenergy to a power signal by generating a magnetic field through theprimary coil(s) and a communication & control unit 120 that controlscommunication with the wireless power receiver 200 and powertransmission so that power may be transmitted at an appropriate level.The system unit 405 may perform control of input power provisioning,control of a plurality of wireless power transmitters, and control ofother operation of the base station such as user interface control.

The primary coil may generate an electromagnetic field by using AC power(or voltage or current). The primary coil may receive AC power (orvoltage or current) at a particular frequency output from the powerconversion unit 110 and generate a magnetic field at the particularfrequency. The magnetic field may be generated in a non-radial or radialdirection, and the wireless power receiver 200 receive the magneticfield to generate a current. In other words, the primary coil transmitspower wirelessly.

In the magnetic induction method, the primary and secondary coils mayhave arbitrarily suitable shapes; for example, the coils may be realizedby copper wires wound around a high permeability member such as ferriteor amorphous metal. The primary coil may also be called primary core,primary winding, or primary loop antenna. Meanwhile, the secondary coilmay also be called secondary core, secondary winding, secondary loopantenna, or pickup antenna.

When the magnetic resonance method is used, the primary and secondarycoils may be provided in the form of a primary resonant antenna and asecondary resonant antenna. A resonant antenna may have a resonancestructure including a coil and a capacitor. At this time, the resonantfrequency of the resonant antenna is determined by the inductance of thecoil and capacitance of the capacitor. Here, the coil may be formed tohave a loop shape. Also, a core may be disposed inside the loop. Thecore may include a physical core such as a ferrite core or an air core.

Energy transfer between the primary resonant antenna and the secondaryresonant antenna may be achieved through the resonance phenomenon of amagnetic field. Resonance is a phenomenon in which high efficiencyenergy transfer occurs between two resonant antennas when one of the tworesonant antennas generates a near field corresponding to the resonantfrequency, the other resonant antenna is located in the vicinity of thefield generating antenna, and the two resonant antennas are coupled toeach other. If a magnetic field corresponding to the resonant frequencyis generated between the first and the second resonant antennas, aphenomenon that the first and the second resonant antennas resonate toeach other occurs; accordingly, the magnetic field is concentratedtowards the secondary resonant antenna with a higher efficiency than anormal case in which the magnetic field generated at the first resonantantenna is radiated into the free space; and thereby energy may betransferred from the first resonant antenna to the secondary resonantantenna with high efficiency. The magnetic induction method may beimplemented similarly to how the magnetic resonance method isimplemented; however, in this case, the frequency of the magnetic fielddoesn't have to be the resonant frequency. Instead, in the magneticinduction method, matching is needed between the loops forming theprimary and the secondary coils, and spacing between the loops has to bevery close.

Although not shown in the figure, the wireless power transmitter 100 mayfurther include a communication antenna. The communication antenna maytransmit and receive a communication signal by using a communicationcarrier in addition to magnetic field communication. For example, thecommunication antenna may transmit and receive a communication signalbased on WiFi, Bluetooth, Bluetooth LE, ZigBee, or NFC.

The communication & control unit 120 may transmit and receiveinformation to and from the wireless power receiver 200. Thecommunication & control unit 120 may include at least one of an IBcommunication module or OB communication module.

The IB communication module may transmit and receive information byusing magnetic waves that use a specific frequency as the centerfrequency. For example, the communication & control unit 120 may performin-band communication by loading information on magnetic waves andtransmitting the magnetic waves through the primary coil or receivemagnetic waves carrying information through the primary coil. At thistime, by using modulation methods like Binary Phase Shift Keying (BPSK)or Amplitude Shift Keying (ASK) scheme or coding methods like Manchestercoding or non-return-to-zero level (NZR-L) coding, information may beloaded into magnetic waves or magnetic waves carrying information may beinterpreted. By using the IB communication, the communication & controlunit 120 may transmit and receive information up to several meters at adata rate of several kbps.

The OB communication module may perform out-band communication throughthe communication antenna. For example, the communication & control unit120 may be provided as a short-range communication module. Examples of ashort-range communication module include communication modules based onWi-Fi, Bluetooth, Bluetooth LE, ZigBee, and NFC.

The communication & control unit 120 may control the overall operationof the wireless power transmitter 100. The communication & control unit120 may perform computation and processing of various pieces ofinformation and control each constituting element of the wireless powertransmitter 100.

The communication & control unit 120 may be implemented by a computer ora device similar to the computer by using hardware, software, or acombination thereof. In hardware, the communication & control unit 120may be provided in the form of an electronic circuit that processeselectric signals and performs control functions. In software, thecommunication & control unit 120 may be provided in the form of aprogram that drives the hardware for the communication & control unit120.

The communication & control unit 120 may control transmission power bycontrolling an operating point. The operating point to be controlled maycorrespond to a combination of a frequency (or phase), duty cycle, dutyratio, and voltage amplitude. The communication & control unit 120 maycontrol transmission power by adjusting at least one of the frequency(or phase), duty cycle, duty ratio, and voltage amplitude. Also, thewireless power receiver 200 may control reception power by controllingthe resonant frequency while the transmitter 100 supplies constantpower.

The mobile device 450 includes a wireless power receiver 200 thatreceives wireless power through the secondary coil and a load 455 thatreceives and stores the power received by the wireless power receiver200 and supplies the stored power to a device.

The wireless power receiver 200 may include a power pick-up unit 210 andcommunication & control unit 220. The power pick-up unit 210 may receivewireless power through the secondary coil and convert the receivedwireless power to electric energy. The power pick-up unit 210 rectifiesan AC signal obtained through the secondary coil to convert to a DCsignal. The communication & control unit 220 may control transmissionand reception of wireless power (power transmission and reception).

The secondary coil may receive wireless power transmitted from thewireless power transmitter 100. The secondary coil may receive power byusing a magnetic field generated at the primary coil. Here, in case aparticular frequency is the resonant frequency, magnetic resonance isgenerated between the primary and secondary coils, and the secondarycoil may receive power more efficiently.

Although not shown in FIG. 4a , the communication & control unit 220 mayfurther include a communication antenna. The communication antenna maytransmit and receive a communication signal by using a communicationcarrier in addition to magnetic field communication. For example, thecommunication antenna may transmit and receive a communication signalbased on WiFi, Bluetooth, Bluetooth LE, ZigBee, or NFC.

The communication & control unit 220 may transmit and receiveinformation to and from the wireless power receiver 100. Thecommunication & control unit 220 may include at least one of an IBcommunication module or OB communication module.

The IB communication module may transmit and receive information byusing magnetic waves that use a specific frequency as the centerfrequency. For example, the communication & control unit 220 may performin-band communication by loading information on magnetic waves andtransmitting the magnetic waves through the secondary coil or receivemagnetic waves carrying information through the secondary coil. At thistime, by using modulation methods like Binary Phase Shift Keying (BPSK)or Amplitude Shift Keying (ASK) scheme or coding methods like Manchestercoding or non-return-to-zero level (NZR-L) coding, information may beloaded into magnetic waves or magnetic waves carrying information may beinterpreted. By using the IB communication, the communication & controlunit 220 may transmit and receive information up to several meters at adata rate of several kbps.

The OB communication module may perform out-band communication throughthe communication antenna. For example, the communication & control unit220 may be provided as a short-range communication module.

Examples of a short-range communication module include communicationmodules based on Wi-Fi, Bluetooth, Bluetooth LE, ZigBee, and NFC.

The communication & control unit 220 may control the overall operationof the wireless power receiver 200. The communication & control unit 220may perform computation and processing of various pieces of informationand control each constituting element of the wireless power receiver200.

The communication & control unit 220 may be implemented by a computer ora device similar to the computer by using hardware, software, or acombination thereof. In hardware, the communication & control unit 220may be provided in the form of an electronic circuit that processeselectric signals and performs control functions. In software, thecommunication & control unit 120 may be provided in the form of aprogram that drives the hardware for the communication & control unit220.

When the communication & control unit 120 and the communication &control unit 220 employ Bluetooth or Bluetooth LE as an OB communicationmodule or short-range communication module, the communication & controlunit 120 and the communication & control unit 220 may operate byimplementing the communication architecture as shown in FIG. 4 b.

FIG. 4b shows one example of a protocol stack of the Bluetooth BasicRate (BR)/Enhanced Data Rate (EDR) that supports GATT and one example ofa protocol stack of Bluetooth Low Energy (LE).

More specifically, the Bluetooth BR/EDR protocol stack may include ancontroller stack 460 and a host stack 470 with respect to a hostcontroller interface (HCI) 18.

The host stack (or host module) 470 refers to hardware for transmittingor receiving a Bluetooth packet to and from a wireless transceivermodule receiving a Bluetooth signal of 2.4 GHz. The controller stack 460is connected to a Bluetooth module and controls the Bluetooth module andperforms an operation.

The controller stack 460 may include a BR/EDR PHY layer 12, a BR/EDRbaseband layer 14, and a link manager 16.

The BR/EDR PHY layer 12 is a layer transmitting and receiving a 2.4 GHzwireless signal, and in case of using Gaussian frequency shift keying(GFSK) modulation, the BR/EDR PHY layer 12 may transmit data by hopping79 RF channels.

The BR/EDR baseband layer 14 serves to transmit a digital signal,selects a channel sequence hopping 1400 times per second, and transmitsa time slot having a length of 625 us for each channel.

The link manager layer 16 controls the overall operation (link setup,control, security) of a Bluetooth connection by utilizing a link managerprotocol (LMP).

The link manager layer 16 may perform the following functions.

-   -   The link manager layer 16 may perform ACL/SCO logical transport,        logical link setup, and control.    -   Detach: The link manager layer 16 stops connection and informs a        counterpart device about the reason for stopping connection.    -   The link manager layer 16 performs power control and role        switch.    -   The link manager layer 16 performs a security (authentication,        pairing, and encryption) function.

The host controller interface layer 18 provides an interface between thehost module and the controller module to allow the host to provide acommand and data to the controller and allow the controller to providean event and data to the host.

The host stack (or host module) 470 includes a logical link control andadaptive protocol (L2CAP) 21, attribute protocol (ATT) 22, genericattribute profile (GATT) 23, generic access profile (GAP) 24, and BR/EDRprofile 25.

The logical link control and adaptive protocol (L2CAP) 21 may provide atwo-way channel for transmitting data to a specific protocol or aprofile.

The L2CAP 21 may multiplex various protocols and profiles provided froma Bluetooth higher position.

The L2CAP of the Bluetooth BR/EDR uses a dynamic channel; supports aprotocol service multiplexer, retransmission, and a streaming mode; andprovides segmentation and reassembly, per-channel flow control, anderror control.

The generic attribute profile (GATT) 23 may operate as a protocoldescribing how the attribute protocol 22 is used in configuringservices. For example, the generic attribute profile 23 may operate tospecify how ATT attributes are grouped together into services andoperate to describe features associated with services.

Thus, the GATT 23 and the ATT 22 may use features in order to describestatus and services of a device and describe how the features arerelated to each other and how the features used.

The attribute protocol 22 and the BR/EDR profile 25 define a service(profile) using the Bluetooth BR/EDR and define an application protocolfor exchanging data; and the generic access profile (GAP) 24 definesdevice discovery, connection and security level.

Next, the Bluetooth LE protocol stack includes a controller stack 480that may be operated to process a wireless device interface for whichtiming is important, and a host stack 490 that may be operated toprocess high level data.

First, the controller stack 480 may be implemented by using acommunication module that may include a Bluetooth wireless device, forexample, a processor module that may include a processing device such asa microprocessor.

The host stack 490 may be implemented as part of an OS operated on theprocessor module or may be implemented as instantiation of a package onthe OS.

In some examples, the controller stack and the host stack may beoperated or executed on the same processing device within the processormodule.

The controller stack 480 includes a physical layer (PHY) 32, link layer(LL) 34, and host controller interface (HCI) 36.

The physical layer (PHY) (wireless transceiver module) 32 is a layer fortransmitting and receiving a 2.4 GHz wireless signal and uses Gaussianfrequency shift keying (GFSK) modulation and a frequency hoppingtechnique including 40 RF channels.

The link layer (LL) 34 serving to transmit or receive a Bluetooth packetprovides a function of generating a connection between devices afterperforming an advertising and scanning function using three advertisingchannels, and exchanging data packets of a maximum of 257 bytes through37 data channels.

The host stack 490 may include a logical link control and adaptationprotocol (L2CAP) 41, security manager (SM) 42, attribute protocol (ATT)43, generic attribute profile (GATT) 44, generic attribute profile (GAP)45, and an LE profile 46. However, the host stack 490 is not limitedthereto and may include various protocols and profiles.

The host stack multiplexes various protocols and profiles provided froma Bluetooth higher position by using the L2CAP.

First, the L2CAP 41 may provide a single two-way channel fortransmitting data to a specific protocol or profile.

The L2CAP 41 may operate to multiplex data between higher layerprotocols, segment and reassemble packages, and manage multicast datatransmission.

In the Bluetooth LE, three fixed channels (one for a signaling channel,one for a security manager, and one for an attribute protocol) arebasically used, and a dynamic channel may be used if necessary.

Meanwhile, in the BR/EDR, a dynamic channel is used by default, and aprotocol service multiplexer, retransmission, streaming mode, and thelike, are supported.

The SM 42 is a protocol for authenticating a device and providing a keydistribution.

The ATT 43 defines a rule for accessing data of a counterpart device ina server-client structure. The ATT 43 includes six types of messages(request, response, command, notification, indication, and confirmation)as follows.

1) Request and Response message: A request message is a message for aclient device to request specific information from a server device, andthe response message, which is a response message with respect to therequest message, refers to a message that may be used for transmissionfrom the server device to the client device.

2) Command message: It is a message transmitted from the client deviceto the server device mainly to indicate a command of a specificoperation. The server device does not transmit a response with respectto the command message to the client device.

3) Notification message: It is a message transmitted from the serverdevice to the client device in order to notify of an event or the like.The client device does not transmit a confirm message with respect tothe notification message to the server device.

4) Indication and confirm message: It is a message transmitted from theserver device to the client device in order to notify of an event or thelike. Unlike the notification message, the client device transmits aconfirm message regarding the indication message to the server device.

In the present disclosure, when the GATT profile using the attributeprotocol (ATT) 43 requests long data, a value regarding a data length istransmitted to allow a client to clearly know the data length, and acharacteristic value may be received from a server by using a universalunique identifier (UUID).

The generic access profile (GAP) 45, which is a layer newly implementedfor the Bluetooth LE technology, is used to select a role forcommunication between Bluetooth LE devices and to control how amulti-profile operation takes place.

Also, the generic access profile (GAP) 45 is mainly used for devicediscovery, connection generation, and security procedure; defines ascheme for providing information to a user; and defines attribute typesas follows.

1) Service: It defines a basic operation of a device by using acombination of behaviors related to data

2) Include: It defines a relationship between services

3) Characteristics: It is a data value used in a service

4) Behavior: It is a format that may be read by a computer defined by aUUID (value type).

The LE profile 46, including profiles dependent upon the GATT, is mainlyapplied to Bluetooth LE devices. The LE profile 46 may include, forexample, Battery, Time, FindMe, Proximity, Time, and the like, anddetails of the GATT-based profiles are as follows.

1) Battery: Battery information exchanging method

2) Time: Time information exchanging method

3) FindMe: Provision of alarm service according to distance

4) Proximity: Battery information exchanging method

5) Time: Time information exchanging method

The generic attribute profile (GATT) 44 may operate as a protocoldescribing how the attribute protocol (ATT) 43 is used when services areconfigured. For example, the GATT 44 may operate to define how ATTattributes are grouped together into services and operate to describefeatures associated with services.

Thus, the GATT 44 and the ATT 43 may use features in order to describestatus and services of a device and describe how the features arerelated to each other and used.

Hereinafter, procedures of the Bluetooth low energy (BLE) technologywill be briefly described.

The BLE procedure may be classified as a device filtering procedure,advertising procedure, scanning procedure, discovering procedure, andconnecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number ofdevices making a response to a request, indication, notification, andthe like in the controller stack.

When requests are received from all the devices, it is not necessary torespond to the requests. Therefore, the controller stack may performcontrol to reduce the number of transmitted requests so that powerconsumption is reduced in the BLE controller.

An advertising device or scanning device may perform the devicefiltering procedure to limit the number of devices receiving anadvertising packet, scan request or connection request.

Here, the advertising device refers to a device transmitting anadvertisement event, that is, a device performing an advertisement andis also termed an advertiser.

The scanning device refers to a device performing scanning, that is, adevice transmitting a scan request.

In the BLE, if the scanning device receives some advertising packetsfrom the advertising device, the scanning device has to transmit a scanrequest to the advertising device.

However, if a device filtering procedure is used and obviates scanrequest transmission, the scanning device may disregard the advertisingpackets transmitted from the advertising device.

Even in a connection request process, the device filtering procedure maybe used. If device filtering is used in the connection request process,it becomes unnecessary to transmit a response to the connection requestby disregarding the connection request.

Advertising Procedure

The advertising device performs an advertising procedure to performundirected broadcast to devices within a region.

Here, the undirected broadcast is advertising toward all the devicesrather than broadcast toward a specific device, and all the devices mayscan advertising to make an additional information request or aconnection request.

In contrast to the undirected broadcast, in the directed broadcast, onlythe device designated as a reception device may make an additionalinformation request or a connection request by scanning advertising.

The advertising procedure is used to establish a Bluetooth connectionwith a nearby initiating device.

Or, the advertising procedure may be used to provide periodicalbroadcast of user data to scanning devices performing listening in anadvertising channel.

In the advertising procedure, all the advertisements (or advertisementevents) are broadcast through an advertisement physical channel.

The advertising devices may receive scan requests from listening devicesperforming listening to obtain additional user data from advertisingdevices. The advertising device transmits a response to the scan requestto the device which has transmitted the scan request through the sameadvertising physical channel in which the scan request has beenreceived.

Broadcast user data sent as part of advertising packets are dynamic datawhile the scan response data is generally static data.

The advertisement device may receive a connection request from aninitiating device on an advertising (broadcast) physical channel. If theadvertising device has used a connectable advertising event and theinitiating device has not been filtered according to the devicefiltering procedure, the advertising device may stop advertising andenter a connected mode. The advertising device may restart advertisingafter the connected mode.

Scanning Procedure

A device performing scanning, that is, a scanning device performs ascanning procedure to listen to undirected broadcast of user data fromadvertising devices using an advertising physical channel.

The scanning device transmits a scan request to an advertising devicethrough an advertising physical channel in order to request additionaldata from the advertising device. The advertising device transmits ascan response in response to the scan request by including thereinadditional user data which has been requested by the scanning devicethrough the advertising physical channel.

The scanning procedure may be used while being connected to other BLEdevice in the BLE piconet.

If the scanning device is in an initiator mode in which the scanningdevice may receive an advertising event and initiate a connectionrequest, the scanning device may transmit a connection request to theadvertising device through the advertising physical channel to start aBluetooth connection with the advertising device.

When the scanning device transmits a connection request to theadvertising device, the scanning device stops the initiator modescanning for additional broadcast and enters the connected mode.

Discovering Procedure

A device available for Bluetooth communication (hereinafter, referred toas “Bluetooth device”) performs an advertising procedure and a scanningprocedure to discover devices in the vicinity thereof or to bediscovered by other devices within a given area.

The discovering procedure is performed asymmetrically. A Bluetoothdevice attempting to discover other nearby device is termed adiscovering device and listens to discover devices advertising anadvertising event that may be scanned. A Bluetooth device which may bediscovered and used by other device is termed a discoverable device andactively broadcasts an advertising event so that it may be scanned byother device through an advertising (broadcast) physical channel.

Both the discovering device and the discoverable device may have alreadybeen connected with other Bluetooth devices in a piconet.

Connecting Procedure

A connecting procedure is asymmetrical and requests that, while aspecific Bluetooth device is performing an advertising procedure, otherBluetooth devices should perform a scanning procedure.

In other words, an advertising procedure may become the goal, and as aresult, only one device may respond to the advertising. After aconnectable advertising event is received from an advertising device, aconnecting request may be transmitted to the advertising device throughan advertising (broadcast) physical channel to initiate connection.

Hereinafter, operational states in the BLE technology, that is, anadvertising state, scanning state, initiating state, and connectionstate will be briefly described.

Advertising State

A link layer (LL) enters an advertising state according to aninstruction from a host (stack). If the LL is in the advertising state,the LL transmits an advertising packet data unit (PDU) from advertisingevents.

Each of the advertising events include at least one advertising PDU, andthe advertising PDUs are transmitted through an advertising channelindexes in use. After the advertising PDU is transmitted through anadvertising channel index in use, the advertising event may beterminated, or if the advertising device needs to secure a space forperforming other function, the advertising event may be terminatedearlier.

Scanning State

The LL enters the scanning state according to an instruction from thehost (stack). In the scanning state, the LL listens to advertisingchannel indexes.

The scanning state includes two types: passive scanning and activescanning. Each of the scanning types is determined by the host.

A separate time period for performing scanning or an advertising channelindex is not defined.

During the scanning state, the LL listens to an advertising channelindex in a scan window (scanWindow) duration. A scan interval(scanInterval) is defined as an interval between start points of twocontiguous scan windows.

When there is no collision in scheduling, the LL should listen in orderto complete all the scan intervals of the scan window as instructed bythe host. In each scan window, the LL should scan other advertisingchannel index. The LL uses every available advertising channel index.

In the passive scanning, the LL only receives packets and is unable totransmit any packet.

In the active scanning, the LL performs listening in order to rely on anadvertising PDU type capable of requesting additional informationrelated to advertising PDUs and an advertising device from theadvertising device.

Initiating State

The LL enters the initiating state according to an instruction from thehost (stack).

When the LL is in the initiating state, the LL performs listening toadvertising channel indexes.

In the initiating state, the LL listens to an advertising channel indexduring the scan window interval.

Connection State

When a device performing a connection request, that is, an initiatingdevice transmits a CONNECT_REQ PDU to an advertising device or when theadvertising device receives a CONNECT_REQ PDU from the initiatingdevice, the LL enters a connection state.

It is considered that a connection is generated after the LL enters theconnection state. However, it is not necessary that the connectionshould be established at the time the LL enters the connection state.The only difference between a newly generated connection and apre-established connection is an LL connection supervision timeoutvalue.

When two devices are connected, the two devices play different roles.

An LL serving as a master is termed a master, and an LL serving as aslave is termed a slave. The master adjusts timing of a connectionevent, and the connection event refers to a time point at which themaster and the slave are synchronized to each other.

Hereinafter, packets defined in the Bluetooth interface will be brieflydescribed. BLE devices use packets as defined below.

Packet Format

The LL has only one packet format used for both of an advertisingchannel packet and a data channel packet.

Each packet includes four fields of a preamble, an access address, aPDU, and a CRC.

When one packet is transmitted in an advertising channel, the PDU maybecome an advertising channel PDU, and when one packet is transmitted ina data channel, the PDU may become a data channel PDU.

Advertising Channel PDU

An advertising channel PDU has a 16-bit header and payload havingvarious sizes.

A PDU type field of the advertising channel PDU included in the heaterindicates PDU types defined in Table 3 below.

TABLE 3 PDU Type Packet Name 0000 ADV_IND 0001 ADV_DIRECT_IND 0010ADV_NONDIRECT_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110ADV_SCAN_IND 0111-1111 Reserved

Advertising PDU

The following advertising channel PDU types are termed advertising PDUsand used in a specific event.

ADV_IND: Connectable undirected advertising event

ADV_DIRECT_IND: Connectable directed advertising event

ADV_NONCONN_IND: Unconnectable undirected advertising event

ADV_SCAN_IND: Scannable undirected advertising event

The PDUs are transmitted from the LL in the advertising state andreceived by the LL in the scanning state or in the initiating state.

Scanning PDU

The following advertising channel DPU types are termed scanning PDUs andare used in a state described below.

SCAN_REQ: Transmitted by the LL in the scanning state and received bythe LL in the advertising state.

SCAN_RSP: Transmitted by the LL in the advertising state and received bythe LL in the scanning state.

Initiating PDU

The following advertising channel PDU type is termed an initiating PDU.

CONNECT_REQ: Transmitted by the LL in the initiating state and receivedby the LL in the advertising state.

Data Channel PDU

The data channel PDU may have a 16-bit header and payload having varioussizes and may include a message integrity check (MIC) field.

The procedures, states, and packet formats in the BLE technologydescribed above may be applied to perform the methods proposed in thepresent specification.

Referring again to FIG. 4a , the load 455 may be a battery. A batterymay store energy by using power output from the power pick-up unit 210.Meanwhile, a battery does not necessarily need to be included in themobile device 450. For example, a battery may be provided as an externalentity in a removable form. In another example, instead of the battery,the wireless power receiver 200 may have a driving means to drivevarious operations of an electronic device.

Although the figure illustrates a case where the mobile device 450includes the wireless power receiver 200, and the base station 400includes the wireless power transmitter 100, the wireless power receiver200 may be considered to be the same as the mobile device 450, and thewireless power transmitter 100 may be considered to be the same as thebase station 400 in a broad sense.

If the communication & control unit 120 and the communication & controlunit 220 include a Bluetooth or Bluetooth LE module as an OBcommunication module or short-range communication module in addition toan IB communication module, the wireless power transmitter 100 includingthe communication & control unit 120 and the wireless power receiver 200including the communication & control unit 220 may be expressed by asimplified block diagram as shown in FIG. 4 c.

FIG. 4c illustrates a block diagram of a wireless power transmissionsystem employing BLE communication according to one example, and FIG. 4dillustrates a block diagram of a wireless power transmission systememploying BLE communication according to another example.

Referring to FIG. 4c , the wireless power transmitter 100 includes apower conversion unit 110 and a communication & control unit 120. Thecommunication & control unit includes an in-band communication module121 and a BLE communication module 122.

Meanwhile, the wireless power receiver 200 includes a power pickup unit210 and a communication & control unit 220. The communication & controlunit 220 includes an in-band communication module 221 and a BLEcommunication module 222.

In one aspect, the BLE communication modules 122, 222 adopt thearchitecture and perform operation according as shown in FIG. 4b . Forexample, the BLE communication modules 122, 222 may be used to establishaccess between the wireless power transmitter 100 and the wireless powerreceiver 200 and to exchange control information and packets requiredfor wireless power transmission.

In another aspect, the communication & control unit 120 may beconfigured to operate a profile for wireless charging. Here, a profilefor wireless charging may be the GATT using BLE transmission.

Meanwhile, the communication & control units 120, 220 may also beimplemented in a way that each of the communication & control unitsincludes only the in-band communication module 121, 221 and the BLEcommunication modules 122, 222 are installed separately from thecommunication & control units 120, 220.

In what follows, a coil or a coil unit may refer to a coil assembly,coil cell, or cell including a coil and at least one element adjacent tothe coil.

In what follows, a coil or a coil unit may refer to a coil assembly,coil cell, or cell including a coil and at least one element adjacent tothe coil.

FIG. 5 is a state transition diagram illustrating a wireless powertransfer procedure.

Referring to FIG. 5, power transmission from a wireless powertransmitter to a wireless power receiver according to one embodiment ofthe present disclosure may be largely divided into a selection phase510, ping phase 520, identification and configuration phase 530,negotiation phase 540, calibration phase 550, power transfer phase 560,and renegotiation phase 570.

The selection phase 510 may be a phase to which the current phase—forexample, it may correspond to S501, S502, S504, S508, S510, andS512—transitions when power transmission is started or a specific erroror a specific event is detected while power transmission is maintained.Here, the specific error or specific event will be made clear from thefollowing description. In addition, in the selection phase 510, thewireless power transmitter may monitor whether an object is present onan interface surface. Upon detecting that the object is present on theinterface surface, wireless power transmission transitions to the pingphase 520. In the selection phase 510, the wireless power transmittermay transmit an analog ping signal with a very short pulse and maydetect whether an object is present in an activate area of the interfacesurface based on a current change in the transmission coil or primarycoil.

If an object is detected in the selection phase 510, the wireless powertransmitter may measure a quality factor of a wireless power resonantcircuit (for example, power transmission coil and/or resonantcapacitor). In one embodiment of the present disclosure, if an object isdetected in the selection phase 510, the quality factor may be measuredto determine whether a wireless power receiver is placed in the chargingarea together with a foreign object. In the case of a coil used for thewireless power transmitter, inductance and/or series resistancecomponent of the coil may be reduced due to environmental change, whichaccordingly reduces the quality factor. To determine existence of aforeign object by using the measured quality factor, the wireless powertransmitter may receive, from the wireless power receiver, a referencequality factor value measured in advance when no foreign object isplaced within the charging area. In the negotiation phase 540, thereceived reference quality factor value is compared with a measuredquality factor value to determine existence of a foreign object.However, in the case of a wireless power receiver where the referencequality factor value is low—for example, a specific wireless powerreceiver may have a low reference quality factor value according to thetype, intended use, and characteristics of the specific wireless powerreceiver—there may not be a significant difference between the measuredquality factor and the reference quality factor even in the presence ofa foreign object, which may cause a problem in determining existence ofthe foreign object. Therefore, existence of a foreign object has to bedetermined by taking into account other decisive factor or by usingother method.

In another embodiment of the present disclosure, if an object isdetected in the selection phase 510, a quality factor within a specificfrequency range (for example, the operating frequency range) may bemeasured to determine whether the wireless power receiver has beendisposed together with a foreign object in the charging area. In thecase of a coil used for the wireless power transmitter, inductanceand/or series resistance component of the coil may be reduced due toenvironmental change, which may accordingly change (shift) the resonantfrequency of the coil of the wireless power transmitter. In other words,the quality factor peak frequency, which is the frequency at which themaximum quality factor value is measured within the operating frequencyrange, may be moved.

In the ping phase 520, upon detecting an object, the wireless powertransmitter may wake up the wireless power receiver and may transmit adigital ping for determining whether the detected object is the wirelesspower receiver. In the ping phase 520, if the wireless power transmitterdoes not receive a response signal to the digital ping, for example, asignal strength packet, from the wireless power receiver, the ping phase620 may re-transition to the selection phase 510. Also, in the pingphase 520, upon receiving a signal indicating that power transmission iscompleted, namely, a charging complete packet, from the wireless powerreceiver, the wireless power transmitter may transition to the selectionphase 510.

When the ping phase 520 is completed, the wireless power transmitter maytransition to the identification and configuration phase 530 foridentifying a wireless power receiver and collecting configuration andstatus information of the wireless power receiver.

In the identification and configuration phase 530, if an unexpectedpacket is received, an expected packet is not received for apredetermined period of time (time out), a transmission error occurs, orno power transfer contact is set, the wireless power transmitter maytransition to the selection phase 510.

The wireless power transmitter may check whether transition to thenegotiation phase 540 is needed based on a negotiation field value of aconfiguration packet received in the identification and configurationphase 530. If it is turned out from the checking result that anegotiation is needed, the wireless power transmitter may enter thenegotiation phase 540 and perform a predetermined Foreign ObjectDetection (FOD) procedure. On the other hand, if it is found from thechecking result that a negotiation is not needed, the wireless powertransmitter may immediately transition to the power transfer phase 560.

In the negotiation phase 540, the wireless power transmitter may receivea Foreign Object Detection (FOD) status packet including a referencequality factor value. Or, the wireless power transmitter may receive anFOD status packet including a reference peak frequency value. Or, thewireless power transmitter may receive a status packet including areference quality factor value and a reference peak frequency value. Atthis time, the wireless power transmitter may determine a qualitycoefficient threshold for FOD based on the reference quality factorvalue. The wireless power transmitter may determine the peak frequencythreshold for FOD based on the reference peak frequency value.

The wireless power transmitter may detect whether a foreign objectexists in a charging area by using a quality coefficient threshold forthe determined FOD and a currently measured quality factor value (aquality factor value measured before the ping phase) and may controlpower transmission according to the FOD result. As one example, if an FOis detected, power transmission may be stopped, but the presentdisclosure is not limited to the specific case.

The wireless power transmitter may detect existence of an FO in acharging area by using the peak frequency threshold for a determined FODand a currently measured peak frequency value (a peak frequency valuemeasured before the ping phase) and may control power transmissionaccording to the FOD result. As one example, if an FO is detected, powertransmission may be stopped, but the present disclosure is not limitedto the specific case.

If an FO is detected, the wireless power transmitter may return to theselection phase 510. On the other hand, if an FO is not detected, thewireless power transmitter may enter the power transfer phase 560 viathe calibration phase 550. More specifically, if an FO is not detected,the wireless power transmitter may determine strength of power receivedby the wireless power receiver in the calibration phase 550 and measurepower loss at the wireless power transmitter and receiver to determinethe strength of power transmitted by the wireless power transmitter. Inother words, the wireless power transmitter may predict power loss basedon a difference between transmission power at the wireless powertransmitter and reception power at the wireless power receiver in thecalibration phase 550. The wireless power transmitter according to oneembodiment may calibrate the threshold for FOD by taking into accountthe predicted power loss.

In the power transfer phase 560, if an unexpected packet is received, anexpected packet is not received for a predetermined period of time (timeout), preset power transfer contract violation occurs, or charging iscompleted, the wireless power transmitter may transition to theselection phase 510.

Also, in the power transfer phase 560, if a power transfer contractneeds to be reconfigured depending on a state change of the wirelesspower transmitter, the wireless power transmitter may transition to therenegotiation phase 570. At this time, if renegotiation is completednormally, the wireless power transmitter may return to the powertransfer phase 560.

The power transfer contract may be set based on state andcharacteristics information of the wireless power transmitter andreceiver. For example, the state information of the wireless powertransmitter may include information about a maximum transmissible poweramount, information about the maximum number of wireless power receiversthat may be accommodated, and so on and the state information of thewireless power receiver may include information about required power andso on.

FIG. 6 illustrates a power control method according to one embodiment.

Referring to FIG. 6, in the power transfer phase, the wireless powertransmitter 100 and the wireless power receiver 200 may control theamount of power transferred by performing power transfer andcommunication at the same time. The wireless power transmitter and thewireless power receiver operate at a specific control point. The controlpoint represents a combination of voltage and current provided at theoutput of the wireless power receiver when power transfer is performed.

To describe in more detail, the wireless power receiver selects adesired control point—desired output current/voltage, temperature at aspecific position on a mobile device, and so on—and additionallydetermines an actual control point currently operating. The wirelesspower receiver may calculate a control error value by using the desiredcontrol point and the actual control point and transmit the calculatedcontrol error value to the wireless power transmitted through a controlerror packet.

And the wireless power transmitter may configure/control a new operatingpoint—amplitude, frequency, and duty cycle—and control power transfer byusing the received control error packet. Therefore, the control errorpacket is transmitted/received at regular time intervals in the powertransfer phase, and as an embodiment, if the wireless power receiverattempts to reduce the current of the wireless power transmitter, thewireless power receiver may transmit the control error value by settingthe control error value to a negative value while, if the wireless powerreceiver attempts to increase the current, the control error value maybe transmitted after being set to a positive value. In this way, in theinduction mode, the wireless power receiver may control power transferby transmitting the control error packet to the wireless powertransmitter.

In the resonance mode to be described below, power transfer may beconducted differently from the induction mode. In the resonance mode,one wireless power transmitter should be able to serve a plurality ofwireless power receivers simultaneously. However, when power transfer iscontrolled as in the induction mode, since transferred power iscontrolled by communication with one wireless power receiver, it may bedifficult to control power transfer for additional wireless powerreceivers. Therefore, in the resonance mode according to the presentdisclosure, a wireless power transmitter transmits basic power commonlyto wireless power receivers, and a wireless power receiver may controlthe amount of received power by controlling its own resonant frequency.However, even in the resonance mode, the method described with referenceto FIG. 6 is not completely excluded; rather, control of additionaltransmission power may be performed according to the method of FIG. 6.

FIG. 7 illustrates a block diagram of a wireless power transmitteraccording to another embodiment. The block diagram may belong to awireless power transmission system in the magnetic resonance method orshared mode. The shared mode may refer to a mode in which wireless powertransmitters and receivers perform one-to-many communication andcharging. The shared mode may be implemented by using the magneticinduction method or resonance method.

Referring to FIG. 7, the wireless power transmitter 700 may include atleast one of a cover 720 covering a coil assembly, power adaptor 730supplying power to a power transmitter 740, power transmitter 740transmitting wireless power, or user interface 750 providing informationabout progress of power transfer and other related matters. Inparticular, the user interface 750 may be optionally included orincluded as another user interface 750 of power transmission equipment.

The power transmitter 740 may include at least one of a coil assembly760, impedance matching circuit 770, inverter 780, communication unit790, or control unit 710.

The coil assembly 760 includes at least one primary coil generating amagnetic field and may be referred to as a coil cell.

The impedance matching circuit 770 provides impedance matching betweenthe inverter 780 and the primary coil(s). The impedance matching circuit770 may generate resonance at a frequency suitable for boosting theprimary coil current. In the multi-coil power transmitter 740, theimpedance matching circuit may additionally include a multiplexer whichroutes a signal to a subset of the primary coils at the inverter 780.The impedance matching circuit 770 may also be referred to as a tankcircuit.

The impedance matching circuit 770 may include capacitors, inductors,and switching elements that switch connections among capacitors andinductors. Matching of impedance may be performed by detecting areflected wave of wireless power transmitted through the coil assembly760 and adjusting a connected state of a capacitor or an inductor byswitching the switching element based on the reflected wave or byadjusting capacitance of a capacitor or by adjusting inductance of aninductor. Depending on the needs, the impedance matching circuit 770 maybe omitted, and the present specification also includes an embodiment ofthe wireless power transmitter 700 in which the impedance matchingcircuit 770 is omitted.

The inverter 780 may convert an DC input to an AC signal. The inverter780 may be driven in a half-bridge or full-bridge structure to generatea pulse wave and duty cycle of an adjustable frequency. Also, theinverter may include a plurality of stages to adjust an input voltagelevel.

The communication unit 790 may perform communication with a powerreceiver. The power receiver performs load modulation to communicate arequest and information with a power transmitter. Therefore, the powertransmitter 740 may monitor amplitude and/or phase of a current and/orvoltage of the primary coil by using the communication unit 790 todemodulate data transmitted from the power receiver.

Also, the power transmitter 740 may control output power to transmitdata through the communication unit 790 by using the Frequency ShiftKeying (FSK) scheme.

The control unit 710 may control communication and power transfer of thepower transmitter 740. The control unit 710 may control power transferby adjusting the aforementioned operating point. The operating point maybe determined, for example, by at least one of the operating frequency,duty cycle, and input voltage.

The communication unit 790 and control unit 710 may be implemented byseparate units/elements/chipsets or by a single unit/element/chipset.

FIG. 8 illustrates a block diagram of a wireless power receiveraccording to another embodiment. The block diagram may belong to awireless power transmission system in the magnetic resonance method orshared mode.

In FIG. 8, the wireless power receiver 800 may include at least one of auser interface 820 providing information about progress of powertransfer and other related matters; power receiver 830 receivingwireless power; and base 850 supporting and covering a load circuit 840or coil assembly. In particular, the user interface 820 may beoptionally included or included as another user interface 820 of powerreception equipment.

The power receiver 830 may include at least one of a power converter860, impedance matching circuit 870, coil assembly 880, communicationunit 890, or control unit 810.

The power converter 860 may convert AC power received from the secondarycoil into voltage and current suitable for the load circuit. As anembodiment, the power converter 860 may include a rectifier. Therectifier rectifies received wireless power and converts an AC signal toa DC signal. The rectifier may convert an AC signal to a DC signal byusing a diode or transistor and smooth the converted signal by using aset of capacitors and resistors. Rectifiers may be implemented by usingfull-wave rectification based on a bridge circuit, half-waverectification, or voltage multiplication. In addition, the powerconverter may adapt to the reflected impedance of the power receiver.

The impedance matching circuit 870 may provide impedance matchingbetween a combination of the power converter 860 and the load circuit840 and the secondary coil. As an embodiment, the impedance matchingcircuit may generate resonance around 100 kHz which may reinforce powertransfer. The impedance matching circuit 870 may include capacitors,inductors, and switching elements that switch between combinationsthereof. Matching of impedance may be performed by controlling switchingelements constituting the impedance matching circuit 870 based on thevoltage, current, power, and frequency value of received wireless power.Depending on the needs, the impedance matching circuit 870 may beomitted, and the present specification also includes an embodiment ofthe wireless power receiver 800 in which the impedance matching circuit870 is omitted.

The coil assembly 880 may include at least one secondary coil andoptionally further include an element which shields a metallic part ofthe receiver against a magnetic field.

The communication unit 890 may perform load modulation to communicate arequest and information with a power transmitter.

To this purpose, the power receiver 830 may switch resistors orcapacitors to change the reflected impedance.

The control unit 810 may control received power. To this purpose, thecontrol unit 810 may determine/calculate a difference between an actualoperating point and a desired operating point of the power receiver 830.And the control unit 810 may adjust/reduce the difference between anactual operating point and a desired operating point by performingadjustment of reflected impedance of the power transmitter and/orfulfilling the operating point adjustment request of the powertransmitter. When this difference is minimized, optimal power receptionmay be performed.

The communication unit 890 and control unit 810 may be implemented byseparate units/elements/chipsets or by a single unit/element/chipset.

FIG. 9 illustrates a communication frame structure according to oneembodiment. This frame structure may be a communication frame structurein the shared mode.

Referring to FIG. 9, in the shared mode, different types of frames maybe used together. For example, in the shared mode, a slotted framehaving a plurality of slots as shown in (A) and a free format framewithout a specific frame as shown in (B) may be used. More specifically,the slotted frame is intended for a wireless power receiver 200 totransmit short data packets to a wireless power transmitter 100, and thefree format frame does not have a plurality of slots, thereby allowingtransmission of long data packets.

Meanwhile, the slotted frame and free format frame may be changed tovarious names by those skilled in the art. For example, the slottedframe may be called a channel frame, and the free format frame may becalled a message frame.

More specifically, the slotted frame may include a sync patternindicating the start of a slot, measurement slot, nine slots, and anadditional sync pattern having the same time interval before each of thenine slots.

Here, the additional sync pattern is different from the sync patternindicating the start of the frame described above. More specifically,the additional sync pattern does not indicate the start of the frame butshows information related to adjacent slots (namely, two consecutiveslots placed at both sides of the sync pattern).

A sync pattern may be located between any two consecutive slots of thenine slots. In this case, the sync pattern may provide informationrelated to the two consecutive slots.

Also, the nine slots and sync patterns provided before the respectivenine slots may have the same time interval. For example, the nine slotsmay have a time interval of 50 ms. Also, the nine sync patterns may havea time length of 50 ms.

Meanwhile, the free format frame as shown in (B) may not have a specificform except for the sync pattern indicating the start of the frame andthe measurement slot. In other words, the free format frame is intendedto perform a role different from that of the slotted frame; for example,the free format frame may be used for performing communication of longdata packets (for example, additional owner information packets) betweena wireless power transmitter and a wireless power receiver or forselecting any one from among a plurality of coils in a wireless powertransmitter composed of the plurality of coils.

In what follows, a sync pattern included in each frame will be describedin more detail with reference to a related figure.

FIG. 10 illustrates a structure of a sync pattern according to oneembodiment.

Referring to FIG. 10, a sync pattern may be composed of a preamble,start bit, response field, type field, info field, and parity bit. InFIG. 10, the start bit is set to ZERO.

More specifically, a preamble is composed of consecutive bits which mayall be set to Os. In other words, the preamble may be composed of bitsto conform to the time length of a sync pattern.

The number of bits constituting the preamble may depend on the operatingfrequency in a way that the length of the sync pattern is closest to 50ms but does not exceed 50 ms. For example, if the operating frequency is100 kHz, the sync pattern may comprise two preamble bits while, if theoperating frequency is 105 kHz, the sync pattern may comprise threepreamble bits.

The start bit is a bit following the preamble and may be set to ZERO.The ZERO may be a bit indicating the type of the sync pattern. Here, thetype of sync pattern may include a frame sync including informationrelated to the frame and a slot sync including information about theslot. In other words, the sync pattern may be a frame sync which islocated between consecutive frames and indicates the start of the frameor a slot sync which is located between consecutive slots among aplurality of slots constituting the frame and includes informationrelated to the consecutive slots.

For example, if the ZERO is 0, it indicates a slot sync where thecorresponding sync is located between slots while, if the ZERO is 1, itindicates a frame sync where the corresponding sync pattern is locatedbetween frames.

The parity bit is the last bit of the sync pattern and indicates thenumber of bits constituting data fields (namely, response field, typefield, and information field) of the sync pattern. For example, theparity bit is 1 when the number of bits constituting data fields of thesync pattern is even and 0, otherwise (namely, when it is odd).

The response field may include response information of a wireless powertransmitter with respect to communication with a wireless power receiverwithin the slot before the sync pattern. For example, the response fieldmay be ‘00’ if communication with the wireless power receiver is notdetected. Similarly, the response field may be ‘01’ if a communicationerror is detected in communication with the wireless power receiver. Thecommunication error may indicate a case in which two or more wirelesspower receivers attempt to approach one slot and two or more wirelesspower receivers collide with each other.

Also, the response field may include information indicating whether adata packet has been received correctly from the wireless powerreceiver. More specifically, the response field may be “10” (10-notacknowledge (NAK)) when the wireless power transmitter denies a datapacket while it may be “11” (11-acknowledge (ACK)) when the wirelesspower transmitter confirms the data packet.

The type field may indicate the type of a sync pattern. Morespecifically, the type field may be ‘1’ to indicate a frame sync if thesync pattern is the first sync pattern of a frame (namely, the firstsync pattern of the frame when the sync pattern is located before themeasurement slot).

Also, the type field may be ‘0’ to indicate a slot sync if the syncpattern is not the first sync pattern of the frame.

Also, the meaning of the information field may be determined accordingto the type of sync pattern indicated by the type field. For example, ifthe type field is 1 (namely in the case of frame sync), the meaning ofthe info field may indicate the type of a frame. In other words, theinfo field may indicate whether a current frame is a slotted frame orfree-format frame. For example, if the info field is ‘00’, it mayindicate a slotted frame while, if the info field is ‘01’, it mayindicate a free-format frame.

Unlike the above, if the type field is 0 (namely in the case of slotsync), the info field may indicate the state of the next slot locatedbehind the sync pattern. More specifically, the info field is ‘00’ ifthe next slot is a slot allocated to a specific wireless power receiver;‘01’ if the next slot is a slot locked to be used temporarily by aspecific wireless power receiver; or ‘10’ if the next slot is a slotfreely available for an arbitrary wireless power receiver.

FIG. 11 illustrates operation states of a wireless power transmitter anda wireless power receiver in a shared mode according to one embodiment.

Referring to FIG. 11, a wireless power receiver operating in the sharedmode may operate in one of selection phase 1100, introduction phase1110, configuration phase 1120, negotiation phase 1130, and powertransfer phase 1140.

First, a wireless power transmitter according to one embodiment maytransmit a wireless power signal to detect a wireless power receiver. Inother words, a process of detecting a wireless power receiver by using awireless power signal may be called analog ping.

Meanwhile, the wireless power receiver which has received a wirelesspower signal may enter the selection phase 1100. The wireless powerreceiver which has entered the selection phase 1100 may detect existenceof an FSK signal on the wireless power signal as described above.

In other words, the wireless power receiver may perform communicationvia either exclusive mode or shared mode depending on existence of theFSK signal.

More specifically, the wireless power receiver may operate in the sharedmode if an FSK signal is included in a wireless power signal andotherwise operate in the exclusive mode.

If the wireless power receiver operates in the shared mode, the wirelesspower receiver may enter the introduction phase 1110. In theintroduction phase 1110, the wireless power receiver may transmit acontrol information (CI) packet to the wireless power transmitter totransmit the CI packet in the configuration phase, negotiation phase,and power transfer phase. The control information packet may have aheader and information related to control. For example, the header ofthe control information packet may be 0X53.

In the introduction state 1110, the wireless power receiver performs anattempt for requesting a free slot to transmit a CI packet throughoutthe subsequent configuration, negotiation, and power transfer phase. Atthis time, the wireless power receiver selects a free slot and transmitsan initial CI packet. If the wireless power transmitter responds to thecorresponding CI with ACK, the wireless power transmitter enters theconfiguration phase. If the wireless power transmitter responds withNACK, it indicates that other wireless power receiver is under progressthrough the configuration and negotiation phase. In this case, thewireless power receiver re-attempts to request a free slot.

If the wireless power receiver receives ACK as a response to the CIpacket, the wireless power receiver determines the location of a privateslot within the frame by counting the remaining slot syncs up to theinitial frame sync. In all subsequent slot based frames, the wirelesspower receiver transmits the CI packet through the corresponding slot.

If the wireless power transmitter allows the wireless power receiver toproceed to the configuration phase, the wireless power transmitterprovides a locked slot series for an exclusive use of the wireless powerreceiver. This ensures that the wireless power receive proceed to theconfiguration phase without collision.

The wireless power receiver transmits sequences of data packets such astwo identification data packets (IDHI and IDLO) by using a locked slot.After completing the present phase, the wireless power receiver entersthe negotiation phase. In the negotiation phase, the wireless powertransmitter continues to provide a locked slot to the wireless powerreceiver for an exclusive use. This ensures that the wireless powerreceiver proceeds the negotiation phase without collision.

The wireless power receiver may transmit one or more negotiation datapackets by using the corresponding locked slot, which may be mixed withprivate data packets. As a result, the corresponding sequence isterminated together with a specific request (SRQ) packet. If thecorresponding sequence is completed, the wireless power receiver entersthe power transfer phase, and the wireless power transmitter stopsproviding a locked slot.

In the power transfer state, the wireless power receiver performstransmission of a CI packet and receives power by using an allocatedslot. The wireless power receiver may include a regulator circuit. Theregulator circuit may be included in the communication & control unit.The wireless power receiver may self-regulate the reflected impedance ofthe wireless power receiver through the regulator circuit. In otherwords, the wireless power receiver may adjust reflected impedance totransmit the amount of power requested by an external load. This mayprevent reception of excessive power and overheating.

In the shared mode, since the wireless power transmitter may not performadjusting power in response to a received CI packet (depending on theoperating mode), control may be necessary to prevent an overvoltagestate.

In what follows, authentication between a wireless power transmitter anda wireless power receiver will be disclosed.

A wireless power transmission system employing in-band communication mayuse USB-C authentication. The authentication includes authentication ofthe wireless power transmitter conducted by the wireless power receiverand authentication of the wireless power receiver conducted by thewireless power transmitter.

FIG. 12 illustrates a wireless charging certificate format according toone embodiment.

Referring to FIG. 12, the wireless charging certificate format includesQi authentication certificate structure version, reserved bit, PTx leaf,certificate type, signature offset, serial number, issuer ID, subjectID, public key, and signature.

In the wireless charging certificate format, the PTx leaf is assigned tothe bits different from those for the certificate type within the samebyte (BO).

The PTx leaf indicates whether the corresponding certificate is a leafcertificate and whether the corresponding certificate is related to awireless power transmitter. In other words, the PTx leaf may indicatewhether the corresponding certificate is a leaf certificate about awireless power transmitter.

The PTx leaf may be a 1-bit indicator. If the PTx leaf is 0, it mayindicate that the corresponding certificate is not a leaf certificate orthat the corresponding certificate is a leaf certificate of a wirelesspower receiver. On the other hand, if the PTx and leaf is 1, it mayindicate that the corresponding certificate is a leaf certificate of awireless power transmitter.

The certificate type, a two-bit indicator, for example, may indicatethat the corresponding certificate is any one of a rootcertificate/intermediate certificate/leaf certificate or may indicateall of the certificates.

FIG. 13 illustrates a data stream at an application level between awireless power transmitter and a wireless power receiver according toone embodiment.

Referring to FIG. 13, a data stream may include an auxiliary datacontrol (ADC) data packer and/or an auxiliary data transport (ADT) datapacket.

The ADC data packet is used for opening a data stream. The ADC datapacket may indicate the type of a message included in the stream and thenumber of data bytes. Meanwhile, the ADT data packet is sequences ofdata containing an actual message. The ADC/end data packet is used toinform of the end of a stream. For example, the maximum number of databytes within a data transmission stream may be limited to 2047.

To notify of normal reception of the ADC and ADT data packets, ACK orNACK is used. Between transmission timing of the ADC and ADT datapackets, information required for wireless charging such as controlerror packet (CEP) or data stream response (DSR) data packet may betransmitted.

By using the data stream structure, authentication-related informationor information at other application level may be transmitted andreceived between a wireless power transmitter and a wireless powerreceiver.

FIG. 14 illustrates a method for exchanging data between a wirelesspower transmitter and a wireless power receiver based on a first timeinterval according to one embodiment. The data exchange methodcorresponds to the protocol for versions lower than the specificationv1.3 of the Wireless Power Consortium (WPC).

Referring to FIG. 14, the control error packet (CEP) is transmitted froma wireless power receiver to a wireless power transmitter in a firsttime interval or with the corresponding period. Here, the first timeinterval between CEPs is a parameter applied to a wireless powertransmitter and a wireless power receiver complying with thespecification of which the version (for example, v1.2.4) is lower thanthe specification v1.3 of the WPC. For example, according to the WPCspecification v1.2.4, the first time interval may be 250 ms. In thiscase, CEP may be transmitted from a wireless power receiver to awireless power transmitter at every 250 ms. Similarly, the target of thefirst time interval may be 250 ms, and the maximum value thereof may begiven as 350 ms. In this case, CEP may be transmitted according to atime interval corresponding to a value ranging from 250 ms to 350 ms.Provided that wireless power transmission is performed in a stablemanner, the first time interval may converge to a relatively constantvalue. In the present specification, the first time interval ranges from250 ms to 350 ms, the target value of the first time interval is 250 ms,and the maximum value of the first time interval is 350 ms. However, theaforementioned values are merely an example, and specific values relatedto the first time interval may be naturally defined by other values. Itshould be noted, however, that specific values related to the first timeinterval are defined to be smaller than the specific values related to asecond time interval to be described later.

Meanwhile, in the extended power profile (EPP), data packets areexchanged through two-way communication. One example of two-waycommunication includes transmission of a data packet by a wireless powertransmitter to a wireless power receiver according to the FrequencyShift Keying (FSK) scheme and transmission of a data packet by thewireless power receiver to the wireless power transmitter according tothe Amplitude Shift Keying (ASK) scheme.

The transmission timing of a data packet should be designed so that thedata packet does not collide with a CEP. Therefore, a data packet at theapplication level such as an ADC data packet, ADT data packet, and DSRdata packet may be transmitted from the wireless power transmitter tothe wireless power receiver or from the wireless power receiver to thewireless power transmitter in a time interval or with a period of theCEP.

FIG. 15 is a flow diagram illustrating operations of a wireless powerreceiver in exchanging data between the wireless power receiver and awireless power transmitter according to the method described withreference to FIG. 14.

Referring to FIG. 15, a wireless power receiver receives wireless powerfrom a wireless power transmitter through magnetic coupling with thewireless power transmitter and converts an AC signal generated by thewireless power to a DC signal S1500. The S1500 step may be performed bya power pick-up unit.

The wireless power receiver calculates a control error (CE) value withrespect to the wireless power received in the power transfer phase fromthe wireless power transmitter S1510. As one example, the wireless powerreceiver may calculate a control error value based on a difference valuebetween the power requested by the wireless power receiver and the powerreceived from the wireless power transmitter. To describe in moredetail, the wireless power receiver may select a desired controlpoint—desired output current/voltage, temperature at a specific positionon a mobile device, and so on—and additionally determine an actualcontrol point currently operating. The wireless power receiver maycalculate a control error value by calculating a difference between thedesired control point and the actual control point and transmit thecalculated control error value to the wireless power transmitted througha control error packet (CEP).

The wireless power receiver configures a control error packet (CEP)including the calculated control error value and transmits theconfigured CEP to the wireless power transmitter in the first timeinterval S1520. If power is received in a stable manner for the wirelesspower receiver to transmit the CEP, the wireless power receiver maytransmit the CEP in the first time interval (for example, 250 ms). Inthis case, the wireless power receiver may transmit a data packet to thewireless power transmitter in the first time interval, or the wirelesspower transmitter may transmit a data packet to the wireless powerreceiver in the first time interval S1530.

Meanwhile, in case the wireless power receiver is unable to receivepower in a stable manner, the wireless power transmitter may transmitthe CEP at shorter time intervals for stable power reception of power.However, since the size of a data packet is fixed, if the time intervalbetween the CEPs becomes short, it is not possible to transmit the datapacket.

For authentication between a wireless power transmitter and a wirelesspower receiver, a large amount of authentication data has to betransmitted and received, and a large amount of data is needed forperforming an additional function by using other data in addition toauthentication. However, the time interval between CEPs may act as alimitation on the transmission of a large amount of data. For example,if the time interval between CEPs is short, since data has to be dividedinto small pieces and transmitted little by little in the time intervalsbetween the CEPs, it takes a considerable time to transmit a largeamount of data.

In other words, if at least one of the wireless power transmitter andthe wireless power receiver complies with a lower version specificationsuch as v1.2.4 of the WPC specification according to FIGS. 14 and 15, aproblem occurs that a considerable time is needed for the wireless powertransmitter and receiver to perform two-way communication based on theEPP.

Therefore, in addition to the first time interval defined in a lowerversion (for example, v1.2.4) of the WPC specification, the presentembodiment defines a new time interval for the CEP, namely a second timeinterval larger than the first time interval, which may be applied to awireless power transmitter and a wireless power receiver developed orimplemented based on a higher version (for example, v1.3) of the WPCspecification. The second time interval may be larger than the firsttime interval by two times or more. More specifically, the maximum valueof the second time interval may be larger than the maximum value of thefirst time interval by two times or more. The present embodiment ishighly applicable to products developed based on the WPC specificationv1.3 and is related to enhancement of performance of a new datatransport protocol specification. Also, the present embodiment disclosesa method for exchanging data when two-way communication is performedthrough an EPP according to the WPC specification.

FIG. 16 illustrates a method for exchanging data between a wirelesspower transmitter and a wireless power receiver based on a second timeinterval according to another embodiment. The data exchange methodcorresponds to the protocol for versions lower than the specificationv1.3 of the Wireless Power Consortium (WPC).

Referring to FIG. 16, the control error packet (CEP) is transmitted froma wireless power receiver to a wireless power transmitter in a secondtime interval or with the corresponding period. Here, the second timeinterval between CEPs is a parameter applied to a wireless powertransmitter and a wireless power receiver complying with thespecification v1.3 of the WPC. For example, according to the WPCspecification v1.3, the second time interval may be 250 ms. In thiscase, CEP may be transmitted from a wireless power receiver to awireless power transmitter at every 250 ms. Similarly, the target of thesecond time interval may be 250 ms, and the maximum value thereof may begiven as 1000 ms. In this case, CEP may be transmitted according to atime interval corresponding to a value ranging from 250 ms to 1000 ms.Similarly, the target of the second time interval may be 250 ms, and themaximum value thereof may be given as 700 ms. In this case, CEP may betransmitted according to a time interval corresponding to a valueranging from 250 ms to 700 ms.

Provided that wireless power transmission is performed in a stablemanner, the second time interval may converge to a relatively constantvalue. In the present specification, the second time interval rangesfrom 250 ms to 1000 ms or from 250 ms to 700 ms, the target value of thesecond time interval is 250 ms, and the maximum value of the second timeinterval is 1000 ms or 700 ms. However, the aforementioned values aremerely an example, and specific values related to the second timeinterval may be naturally defined by other values. It should be noted,however, that the other values may be defined to be larger than thespecific values related to the aforementioned second time interval.

FIG. 17 is a flow diagram illustrating operations of a wireless powerreceiver in exchanging data between the wireless power receiver and awireless power transmitter according to the method described withreference to FIG. 16.

Referring to FIG. 17, a wireless power receiver receives wireless powerfrom a wireless power transmitter through magnetic coupling with thewireless power transmitter and converts an AC signal generated by thewireless power to a DC signal S1700. The S1700 step may be performed bya power pick-up unit.

The wireless power receiver increases or sets the time interval betweenCEPs to the second time interval (for example, a maximum value of 700 msor 1000 ms) S1710. Here, the operation for the wireless power receiverto set or change the time interval between the CEPs to the second timeinterval may be defined by using various embodiments.

In one example, when wireless power is received in a stable manner, thewireless power receiver may set or change the time interval between theCEPs to the second time interval. When reception of wireless power isunstable, it may be difficult to increase the time interval between theCEPs because precise power control is needed.

In another example, in case both of a wireless power transmitter and awireless power receiver comply with the WPC specification v1.3 andperform two-way communication based on the EPP, the wireless powerreceiver may set or change the time interval between the CEPs to thesecond time interval. As described above, since only the first timeinterval is defined in lower versions of the WPC specification (forexample, v1.2.4), there is a limitation in supporting transmission of alarge amount of data. Accordingly, the present disclosure defines thesecond time interval that complies with v1.3, a higher version of theWPC specification, in addition to the first time interval to supporttransmission of a large amount of data. It should be noted, however,that even if one of the wireless power receiver and the wireless powertransmitter supports v1.3, a higher version of the WPC specification,only the first time interval according to a lower version of the WPCspecification is used as the time interval between the CEPs if the otherone supports the lower version of the WPC specification. Therefore,according to the present disclosure, if both of a wireless powertransmitter and a wireless power receiver comply with v1.3 of the WPCspecification and perform two-way communication based on the EPP, thewireless power receiver may set or change the time interval between theCEPs to the second time interval.

In yet another example, after transmitting a CEP time change packet thatindicates increasing or changing the time interval between the CEPs tothe wireless power transmitter, the wireless power receiver may set orchange the time interval between the CEPs to the second time interval.In changing the time interval between the CEPs to the second timeinterval rather than the first time interval, the wireless powerreceiver may first signal the attempt explicitly to the wireless powertransmitter to perform changing or increasing the time interval betweenthe CEPs.

In still yet another example, when a large amount of data in a higherlayer such as authentication or security have to be transmitted, thewireless power receiver may set or change the time interval between theCEPs to the second time interval. This is so because, if transmission isaccommodated despite the first time interval, for example, a case wherea small amount of data has to be transmitted or received, a datatransmission delay does not occur even if the wireless power receiverdoes not deliberately increase the time interval between the CEPs to thesecond time interval while both of the wireless power transmitter andthe wireless power receiver support v1.3 of the WPC specification. Inother words, the second time interval as a time interval between theCEPs may be used selectively by the wireless power receiver if a largeamount of data in a higher layer such as authentication or security haveto be transmitted.

The wireless power receiver calculates a control error (CE) value withrespect to the wireless power received in the power transfer phase fromthe wireless power transmitter S1720. As one example, the wireless powerreceiver may calculate a control error value based on a difference valuebetween the power requested by the wireless power receiver and the powerreceived from the wireless power transmitter. To describe in moredetail, the wireless power receiver may select a desired controlpoint—desired output current/voltage, temperature at a specific positionon a mobile device, and so on—and additionally determine an actualcontrol point currently operating. The wireless power receiver maycalculate a control error value by calculating a difference between thedesired control point and the actual control point and transmit thecalculated control error value to the wireless power transmitted througha CEP.

The wireless power receiver configures a control error packet (CEP)including the calculated control error value and transmits theconfigured CEP to the wireless power transmitter in the second timeinterval S1730. In this case, the wireless power receiver may transmit adata packet to the wireless power transmitter in the second timeinterval, or the wireless power transmitter may transmit a data packetto the wireless power receiver in the second time interval S1740.

As described above, if the time interval between the CEPs is increasedfrom the first time interval to the second time interval, a need fordividing a large amount of data into smaller segments is reduced, anddata with a larger size may be transmitted in the time intervals betweenthe CEPs. Therefore, a time needed for transmitting or receiving a largeamount of data between the wireless power transmitter and the wirelesspower receiver.

As described with reference to FIGS. 14 to 17, the time interval betweenCEPs may be set to the first time interval according to FIG. 14 or FIG.15 or to the second time interval according to FIG. 16 or FIG. 17depending on the WPC specification with which the wireless powertransmitter and the wireless power receiver comply and whether two-waycommunication based on the EPP is supported. More specifically, if atleast one of the wireless power transmitter and the wireless powerreceiver supports a lower version (for example, v1.2.4) than v1.3 of theWPC specification as shown in FIG. 14 or FIG. 15, the time intervalbetween the CEPs may be set to the first time interval. And if both ofthe wireless power transmitter and the wireless power receiver complywith v1.3 of the WPC specification as shown in FIG. 16 or FIG. 17, andtwo-way communication based on the EPP is performed, the time intervalbetween CEPs may be set to the second time interval.

In other words, based on a type of a power profile and a version ofwireless power transfer standard with which the wireless power receptionand the wireless power transmitter comply, the wireless power receivermay transmit a CEP including a control error value for wireless power tothe wireless power transmitter in the first time interval or second timeinterval larger than the first time interval.

The wireless power transmitter in the embodiments of FIGS. 14 to 17corresponds to the wireless power transmitter or power transmitter ortransmitter disclosed in FIGS. 1 to 11. Therefore, the operation of thewireless power transmitter in the embodiments of FIGS. 14 to 17 isimplemented by a combination of one or two or more constituting elementsof the wireless power transmitter of FIGS. 1 to 11. For example,reception of a CEP, processing of data (or packet or signal), andtransmission and reception operation by the wireless power transmitterin FIGS. 14 to 17 may be performed by the communication & control unit120. Also, the wireless power receiver in the embodiments of FIGS. 14 to17 corresponds to the wireless power receiver or power receiver orreceiver disclosed in FIGS. 1 to 11. Therefore, the operation of thewireless power receiver in the embodiments of FIGS. 14 to 17 isimplemented by a combination of one or two or more constituting elementsof the wireless power receiver of FIGS. 1 to 11. For example, generationof a CEP, configuration of the time interval between CEPs, processing ofdata (or packet or signal) according to the first time interval or thesecond time interval, and transmission and reception operation by thewireless power receiver in the present embodiment may be performed bythe communication & control unit 220.

As one example, suppose the time interval between CEPs is changed by thewireless power transmitter. If it is confirmed that the time intervalbetween CEPs is stabilized while power is being transmitted to thewireless power receiver in the power transfer phase, the communication &control unit 120 of the wireless power transmitter may increase the timeinterval between CEPs and at the same time, transmit information aboutthe increased time interval between CEPs to the wireless power receiver.In this case, the communication & control unit 220 of the wireless powerreceiver may deal with the increased time interval between CEPs byincreasing the time interval between CEPs and/or CE time-out based onthe information about the time interval between CEPs received from thewireless power transmitter. Afterwards, the communication & control unit120 may transmit a large amount of data in the increased time intervalbetween CEPs and transmit information for restoring the previous timeinterval between CEPs if it is confirmed that the wireless powerreceiver has fully received the large amount of data.

As another example, suppose the time interval between CEPs is changed bythe wireless power receiver. If it is confirmed that the time intervalbetween CEPs is stabilized while power is being received from thewireless power transmitter in the power transfer phase, thecommunication & control unit 220 of the wireless power receiver mayincrease the time interval between CEPs and at the same time, transmitinformation about the increased time interval between CEPs to thewireless power transmitter. If the communication & control unit 120 ofthe wireless power transmitter receives information about the increasedtime interval between CEPs from the wireless power receiver, thecommunication & control unit 120 may deal with the increased timeinterval between CEPs by increasing the time interval between CEPsand/or CE time-out based on the received information. Afterwards, thecommunication & control unit 220 may transmit a large amount of data tothe wireless power transmitter in the increased time interval betweenCEPs. Then if it is confirmed that the wireless power transmitter hasfully received the large amount of data, the communication & controlunit 220 may transmit information for restoring the time intervalbetween CEPs increased temporarily for transmission of the large amountof data.

FIG. 18 is a flow diagram illustrating operations of a wireless powertransmitter in exchanging data between a wireless power receiver and thewireless power transmitter according to one embodiment.

Referring to FIG. 18, the wireless power transmitter transmits wirelesspower to the wireless power receiver through magnetic coupling with thewireless power receiver S1800. The S1800 step may be performed by thepower conversion unit.

The wireless power transmitter drives CEP time-out CEP time-out based onthe time interval between CEP selected by the wireless power receiverS1810. The CEP time-out corresponds to a maximum time for which thewireless power transmitter may receive a CEP from the wireless powerreceiver, and if a CEP is not received within the CEP time-out, thewireless power transmitter treats the situation as a “CEP not received”case.

The CEP time-out may be configured variably within a range which islarger than a predetermined minimum value. Here, the minimum value ofthe CEP time-out should be larger than at least the maximum value of thetime interval between CEPs. Otherwise, the CEP time-out may be appliedeven for normal CEPs. Therefore, if the time interval between CEPs ischanged or increased, the CEP time-out is changed or increasedaccordingly.

The operation for the wireless power transmitter to set or change theCEP time-out based on the second time interval may be defined by usingvarious embodiments.

In one example, when wireless power is received in a stable manner, thewireless power transmitter may configure the CEP time-out according tothe second time interval.

In another example, in case both of a wireless power transmitter and awireless power receiver comply with the WPC specification v1.3 andperform two-way communication based on the EPP, the wireless powertransmitter may configure the CEP time-out according to the second timeinterval.

In yet another example, after receiving a CEP time change packet thatindicates increasing or changing the time interval between the CEPs fromthe wireless power receiver, the wireless power transmitter mayconfigure the CEP time-out according to the second time interval.

In still yet another example, when a large amount of data in a higherlayer such as authentication or security have to be transmitted, thewireless power transmitter may configure the CEP time-out according tothe second time interval

In the examples above, the CEP time-out due to the second time intervalbetween CEPs may be set to range from 700 ms to 1800 ms. If the secondtime interval (where the maximum value thereof is 700 ms) is used as thetime interval between CEPs, the CEP time-out may be set to any valuelarger than 700 ms. If the first time interval (where the maximum valuethereof is 250 ms or 350 ms) is used as the time interval between CEPs,the CEP time-out may be set to any value larger than 250 ms or 350 ms.As described above, depending on the time interval between CEPs, the CEPtime-out may be varied, and the first CEP time-out when the timeinterval between CEPs is the first time interval is smaller than thesecond CEP time-out when the time interval between CEPs is the secondtime interval. The first time interval between CEPs is used for a lowerversion (for example, v1.2.4) of the WPC specification while the secondtime interval between CEPs is used for a higher version (for example,v1.3) of the WPC specification. Therefore, if the CEP time-out isdefined from a perspective of the WPC specification, the CEP time-outmay be set to the second time-out when the version of the WPCspecification is v1.2.4, and the type of a power profile is EPP.

The wireless power transmitter receives a CEP in the first time intervalor second time interval S1820. And the wireless power transmitter maytransmit a data packet to the wireless power receiver or receive a datapacket from the wireless power receiver in the first time interval orsecond time interval S1830.

FIG. 19 is a flow diagram illustrating operations of a wireless powerreceiver in exchanging data between a wireless power receiver and thewireless power transmitter according to another embodiment.

Referring to FIG. 19, the wireless power receiver repeats a process atpredetermined intervals, where the wireless power receiver calculates aCE value with respect to the power transmitted by the wireless powertransmitter in the power transfer phase S1900 and configures a CEPincluding the calculated CE value and transmits the configured CEP tothe wireless power transmitter S1910. In the present embodiment, methodsdescribed with reference to FIGS. 1 to 11 may be performed until thewireless power transmitter and the wireless power receiver come close tothe power transfer phase, and the time interval between CEPs isstabilized. Stabilization of the time interval between CEPs indicatesthat power transfer is being performed in a stable manner. Also,stabilization of the time interval between CEPs indicates that noproblem is occurred in sending a large amount of data. Therefore,according to the present disclosure, the wireless power receiver maycheck whether the time interval between CEPs has been stabilized totransmit a large amount of data S1920. If it is determined that the timeinterval between CEPs has not been stabilized yet, namely, a load ischanging rapidly, the wireless power receiver may transmit and receive adata packet to and from the wireless power transmitter in a timeinterval between the corresponding CEPs S1930.

If the time interval between CEPs is stabilized, the wireless powerreceiver may adjust (change) the time interval between CEPs from theprevious value of 250 ms to a value larger than 250 ms so that a largeamount of data may be transmitted in one CEP time interval S1940. Also,if the time interval between CEPs is changed, the wireless powerreceiver may inform the wireless power transmitter, by transmittinginformation related to the time interval between CEPs to the wirelesspower transmitter, that the wireless power receiver is ready to transmita large amount of data to the wireless power transmitter. If thewireless power transmitter receives information related to the timeinterval between CEPs from the wireless power receiver, the wirelesspower transmitter may transmit a large amount of data to the wirelesspower receiver by adjusting the time interval between CEPs based on thereceived information or receive a large amount of data from the wirelesspower receiver by adjusting the CE time-out. Here, the informationrelated to the time interval between CEPs may include time intervalchange information between CEPs, CE time-out change information,information for restoring the time interval between CEPs, andinformation about duration of the changed time interval between CEPs.

Meanwhile, the apparatus which starts adjusting of the time intervalbetween CEPs may be the wireless power transmitter. In this case, if thetime interval between CEPs is stabilized, the wireless power transmittermay adjust the time interval between CEPs from the previous value of 250ms to a value larger than 250 ms and prepare for transmitting a largeamount of data. And the wireless power transmitter may transmitinformation related to the changed time interval between CEPs to thewireless power receiver S1950. If the wireless power receiver receivesinformation related to the changed time interval between CEPs, thewireless power receiver may transmit a large amount of data to thewireless power transmitter by adjusting the time interval between CEPsor receive a large amount of data from the wireless power transmitter byadjusting the CE time-out.

Through the process described above, the wireless power transmitter andthe wireless power receiver may receive a large amount of data withinthe changed (increased) time interval between CEPs and performadditional functions. Here, the additional functions refer to functionsusing a large amount of data, which include an authentication procedureas a typical example.

The wireless power transmitter in the present embodiment corresponds tothe wireless power transmitter or power transmitter or transmitterdisclosed in FIGS. 1 to 11. Therefore, the operation of the wirelesspower transmitter in the present embodiment is implemented by acombination of one or two or more constituting elements of the wirelesspower transmitter of FIGS. 1 to 11. For example, processing of data (orpacket or signal) and transmission and reception operation by thewireless power transmitter in the present embodiment may be performed bythe communication & control unit 120. Also, the wireless power receiverin the present embodiment corresponds to the wireless power receiver orpower receiver or receiver disclosed in FIGS. 1 to 11. Therefore, theoperation of the wireless power receiver in the present embodiment isimplemented by a combination of one or two or more constituting elementsof the wireless power receiver of FIGS. 1 to 11. For example, processingof data (or packet or signal) and transmission and reception operationby the wireless power receiver in the present embodiment may beperformed by the communication & control unit 220.

As one example, suppose the time interval between CEPs is changed by thewireless power transmitter. If it is confirmed that the time intervalbetween CEPs is stabilized while power is being transmitted to thewireless power receiver in the power transfer phase, the communication &control unit 120 of the wireless power transmitter may increase the timeinterval between CEPs and at the same time, transmit information aboutthe increased time interval between CEPs to the wireless power receiver.In this case, the communication & control unit 220 of the wireless powerreceiver may deal with the increased time interval between CEPs byincreasing the time interval between CEPs and/or CE time-out based onthe information about the time interval between CEPs received from thewireless power transmitter. Afterwards, the communication & control unit120 may transmit a large amount of data in the increased time intervalbetween CEPs and transmit information for restoring the previous timeinterval between CEPs if it is confirmed that the wireless powerreceiver has fully received the large amount of data.

As another example, suppose the time interval between CEPs is changed bythe wireless power receiver. If it is confirmed that the time intervalbetween CEPs is stabilized while power is being received from thewireless power transmitter in the power transfer phase, thecommunication & control unit 220 of the wireless power receiver mayincrease the time interval between CEPs and at the same time, transmitinformation about the increased time interval between CEPs to thewireless power transmitter. If the communication & control unit 120 ofthe wireless power transmitter receives information about the increasedtime interval between CEPs from the wireless power receiver, thecommunication & control unit 120 may deal with the increased timeinterval between CEPs by increasing the time interval between CEPsand/or CE time-out based on the received information. Afterwards, thecommunication & control unit 220 may transmit a large amount of data tothe wireless power transmitter in the increased time interval betweenCEPs. Then if it is confirmed that the wireless power transmitter hasfully received the large amount of data, the communication & controlunit 220 may transmit information for restoring the time intervalbetween CEPs increased temporarily for transmission of the large amountof data.

FIG. 20 is a flow diagram illustrating a method for exchanging databetween a wireless power transmitter and a wireless power receiveraccording to another embodiment.

Referring to FIG. 20, described will be a method for transmitting alarge amount of data by adjusting the time interval between CEPs of atransmitter and the CEP time-out of a receiver provided that the timeinterval between CEPs has been stabilized. Here, if the transmitter is awireless power transmitter, the receiver corresponds to a wireless powerreceiver, and if the transmitter is a wireless power receiver, thereceiver corresponds to a wireless power transmitter.

A CEP is a data packet including a control error (CE) value. A CE valueis a difference value between a value set as a target and a currentlytransmitted value. In case power is transmitted in a stable manner, thedifference value is close to ‘0’. Therefore, that CE values within aplurality of CEPs are maintained within a specific range means thatpower transfer is being conducted in a stable manner. In this case, eachCEP is transmitted at predetermined intervals. In other words, the timeinterval between CEPs is stabilized. In what follows, such a situationwill be called a normal situation or a stabilized situation. As oneexample, FIG. 20 illustrates a case where a CEP is transmitted atintervals of 250 ms in the stabilized situation. In this situation, thetransmitter may transmit time interval change information between CEPsincluding information for increasing the time interval between CEPs totransmit a large amount of data in a time period between the first CEPand the second CEP, namely in the time interval between CEPs. The timeinterval change information between CEPs may be transmitted in the formof a data packet at the application level.

The receiver, which has received a signal indicating that the timeinterval between CEPs is increased beyond 250 ms, namely the timeinterval change information between CEPs, may prepare for receiving alarge amount of data by adjusting a CE time-out. Here, the receiver mayset the length of the CE time-out to be longer than the length of thechanged time interval between CEPs. For example, suppose the timeinterval between CEPs is set to 250 ms, and the CE time-out is set to800 ms. If the transmitter informs the receiver that the transmitterchanges the time interval between CEPs to 1000 ms, the receiver maychange the CE time-out from 800 ms to 1500 ms. Meanwhile, as oneexample, although FIG. 20 illustrates a case where the time intervalbetween CEPs is increased from 250 ms to 1000 ms, the time intervalbetween CEPs may be made longer than 1000 ms.

If the time interval between CEPs is increased, the transmitter may senda large amount of data during the increased time interval between CEPs.And if transmission of data is completed, the time interval changeinformation between CEPs including information for restoring the timeinterval between CEPs is transmitted, and the time interval between CEPsmay be restored to 250 ms.

Similarly, the transmitter may transmit information about a period forwhich the increased time interval between CEPs together when the timeinterval change information between CEPs is transmitted. In this case,even if no time interval change information between CEPs is receivedseparately from the transmitter, the receiver may restore the timeinterval between CEPs after the corresponding period is elapsed.

Due to the procedure above, even if the transmitter adjusts the timeinterval between CEPs to send a large amount of data, since the time atwhich the receiver falls into a time-out as it fails to receive a CEP isadjusted, a large amount of data may be transmitted and received in astable manner. Also, due to this feature, a charging time may be morereduced than conventional methods, and additional functions including anauthentication procedure may be utilized.

Since not all constituting elements or phases are essential for awireless power transmission apparatus and method or a wireless powerreception apparatus and method according to embodiments of the presentdisclosure described above, the wireless power transmission apparatusand method or the wireless power reception apparatus and method may beperformed by including whole or part of the constituting elements orphases described above. Also, embodiments of the wireless powertransmission apparatus and method or the wireless power receptionapparatus and method may be performed in combination thereof. Also, theconstituting elements or phases do not necessarily have to be performedin the specific order described above, and a phase described later maybe performed before a phase described earlier.

The description given above is merely an embodiment for illustratingtechnical principles of the present disclosure, and various changes andmodifications are possible from the disclosure by those skilled in theart to which the present disclosure belongs without deviating from theinherent characteristics of the present disclosure. Therefore, it ispossible that embodiments of the present disclosure described above maybe implemented individually or in a combination thereof.

Therefore, it should be understood that embodiments disclosed in thepresent specification are not intended to limit the technical principlesof the present disclosure but to support describing the presentdisclosure, and thus the technical scope of the present disclosure isnot limited by the embodiments. The technical scope of the presentdisclosure should be judged by the appended claims, and all of thetechnical principles found within the range equivalent to the technicalscope of the present disclosure should be interpreted to belong thereto.

1. A wireless power receiver for receiving wireless power from awireless power transmitter and for transmitting a control packet to thewireless power transmitter in a wireless power transfer system, thewireless power receiver comprising: a power pick-up unit configured toreceive wireless power from the wireless power transmitter via magneticcoupling with the wireless power transmitter, and to convert an ACsignal generated by the wireless power to a DC signal; acommunication/control unit configured to receive the DC signal from thepower pick-up unit, and to perform control of the wireless power; and aload configured to receive the DC signal from the power pick-up unit,wherein the communication/control unit is configured to transmit acontrol error packet including a control error value for the wirelesspower to the wireless power transmitter in a first time interval or asecond time interval larger than the first time interval, based on atype of a power profile and a version of wireless power transferstandard with which the wireless power receiver and the wireless powertransmitter comply.
 2. The wireless power receiver of claim 1, wherein,if the version of the wireless power transfer standard is a firstversion, the communication/control unit transmits the control errorpacket in a first time interval while, if the version of the wirelesspower transfer standard is a second version higher than the firstversion and a type of the power profile is extended power profile (EPP),the communication/control unit transmits the control error packet in asecond time interval.
 3. The wireless power receiver of claim 1,wherein, if the version of the wireless power transfer standard is afirst version, the communication/control unit transmits the controlerror packet in the first time interval while, if the version of thewireless power transfer standard is a second version higher than thefirst version, a type of the power profile is EPP, and transmission of adata packet is needed, the communication/control unit transmits thecontrol error packet in the second time interval.
 4. The wireless powerreceiver of claim 2, wherein the wireless power transfer standard is theWireless Power Consortium (WPC) specification, the first version islower than v1.3, and the second version is v1.3.
 5. The wireless powerreceiver of claim 2, wherein the first time interval is larger than thesecond time interval by two times or more.
 6. The wireless powerreceiver of claim 1, wherein, according to a type of a power profile anda version of wireless power transfer standard with which the wirelesspower receiver and the wireless power transmitter comply, time-out ofthe control error packet is determined as a first time-out or a secondtime-out larger than the first time-out.
 7. The wireless power receiverof claim 6, wherein, if a version of the wireless power transferstandard is a first version, the time-out for the control error packetis determined as the first time-out while, if a version of the wirelesspower transfer standard is a second version higher than the firstversion and type of the power profile is EPP, the time-out for thecontrol error packet is determined as the second time-out.
 8. Thewireless power receiver of claim 6, wherein the first time interval issmaller than the first time-out, and the second time interval is smallerthan the second time-out.
 9. A wireless power transmitter transmittingwireless power to a wireless power receiver and receiving a controlpacket from the wireless power receiver in a wireless power transfersystem, the wireless power transmitter comprising: a power conversionunit configured to transmit wireless power to the wireless powerreceiver via magnetic coupling with the wireless power receiver; and acommunication/control unit configured to receive a control error packetincluding a control error value for the wireless power from the wirelesspower receiver in a first time interval or a second time interval largerthan the first time interval based on a type of a power profile and aversion of wireless power transfer standard with which the wirelesspower receiver and the wireless power transmitter comply.
 10. Thewireless power transmitter of claim 9, wherein, if the version of thewireless power transfer standard is a first version, thecommunication/control unit receives the control error packet in thefirst time interval while, if the version of wireless power transferstandard is a second version higher than the first version and a type ofthe power profile is extended power profile (EPP), thecommunication/control unit receives the control error packet in thesecond time interval.
 11. The wireless power transmitter of claim 9,wherein, if the version of the wireless power transfer standard is thefirst version, the communication/control unit receives the control errorpacket in the first time interval while, if the version of the wirelesspower transfer standard is the second version higher than the firstversion, the type of the power profile is EPP, and transmission of adata packet is needed, the communication/control unit receives thecontrol error packet in the second time interval.
 12. The wireless powertransmitter of claim 10, wherein the wireless power transfer standard isthe Wireless Power Consortium (WPC) specification, the first version islower than v1.3, and the second version is v1.3.
 13. The wireless powertransmitter of claim 10, wherein the first time interval is larger thanthe second time interval by two times or more.
 14. The wireless powertransmitter of claim 9, wherein, according to a type of a power profileand a version of wireless power transfer standard with which thewireless power receiver and the wireless power transmitter comply,time-out of the control error packet is determined as a first time-outor a second time-out larger than the first time-out.
 15. The wirelesspower transmitter of claim 13, wherein, if a version of the wirelesspower transfer standard is a first version, the time-out for the controlerror packet is determined as the first time-out while, if a version ofthe wireless power transfer standard is a second version higher than thefirst version and type of the power profile is EPP, the time-out for thecontrol error packet is determined as the second time-out.
 16. Thewireless power transmitter of claim 14, wherein the first time intervalis smaller than the first time-out, and the second time interval issmaller than the second time-out.
 17. The wireless power receiver ofclaim 3, wherein the wireless power transfer standard is the WirelessPower Consortium (WPC) specification, the first version is lower thanv1.3, and the second version is v1.3.
 18. The wireless power receiver ofclaim 3, wherein the first time interval is larger than the second timeinterval by two times or more.
 19. The wireless power transmitter ofclaim 11, wherein the wireless power transfer standard is the WirelessPower Consortium (WPC) specification, the first version is lower thanv1.3, and the second version is v1.3.
 20. The wireless power transmitterof claim 11, wherein the first time interval is larger than the secondtime interval by two times or more.